AS SSD Benchmark vs CrystalDiskInfo: Benchmark vs Health Monitor

AS SSD Benchmark and CrystalDiskInfo are confused constantly, partly because their names sit next to each other in download lists and partly because both are free Windows staples. But they do opposite kinds of work. AS SSD Benchmark actively stresses a drive and times it. CrystalDiskInfo passively reads the drive’s own self-monitoring data and reports its condition. A fast drive can be dying; a healthy drive can be slow. This page explains the division of labour — what AS SSD does not tell you, what CrystalDiskInfo does not tell you, and how to use the two together. AS SSD is available on our download page.

What AS SSD Benchmark tells you — and what it never will

AS SSD measures performance: sequential throughput, 4K and 4K-64Thrd random throughput, access time, copy-test times for ISO, Program and Game file sets, and throughput across data compressibility. It summarises the synthetic tests into a total score, and its header shows the drive model, firmware, controller driver and alignment status. All of that describes how the drive performed during a few minutes of testing, on that day, in that system.

Here is the list it does not cover, in full: no SMART attributes, no health percentage, no temperature, no power-on hours, no total bytes written, no remaining-life estimate, no error counts, no firmware update, no secure erase. AS SSD has no health features at all — it is a benchmark, not a monitor. A drive one week from failure can post a perfectly respectable score, because failing drives often perform normally until they do not. If your question contains the words health, lifespan, temperature, wear or safe, AS SSD is the wrong tool no matter how good its score looks. To understand the scores themselves once you have them, read how to read AS SSD scores.

What CrystalDiskInfo tells you — and what it never will

CrystalDiskInfo, from the same Crystal Dew World project family as CrystalDiskMark, reads the SMART (Self-Monitoring, Analysis and Reporting Technology) data that drives maintain about themselves. It presents a plain health status, the drive’s temperature, and the underlying attributes — items such as wear indicators, error counts, power-on time and the volume of data written, depending on what the drive exposes. It can sit in the background and warn you when a value crosses a threshold. That is exactly the early-warning system a benchmark cannot provide: it watches the drive’s own account of its condition, continuously, without running a single speed test.

Its blind spot is the mirror image of AS SSD’s: CrystalDiskInfo cannot tell you how fast anything is. A drive can report perfect health while delivering miserable performance because it is nearly full, connected to a slow port, running in the wrong controller mode or simply an old, slow model in flawless condition. Health data also depends on the drive reporting honestly and completely; treat a clean SMART report as strong reassurance, not a guarantee, and keep backups regardless. (For deeper diagnostic work such as full surface scans, a suite like HD Tune Pro goes further — see AS SSD Benchmark vs HD Tune.)

Side-by-side comparison

Dimension	AS SSD Benchmark	CrystalDiskInfo
What it measures	Active performance tests: Seq, 4K, 4K-64Thrd, access time, Copy and Compression	No measurement — reads SMART health data: status, temperature, wear and error attributes
Score / result form	MB/s or IOPS per test plus a weighted Total score	Health status verdict and an attribute table with current and threshold values
Platform	Windows only; portable	Windows
Licence and price	Freeware by Alexej Schepeljanski; free	Free, from Crystal Dew World (Noriyuki Miyazaki’s project family)
Maintenance status	Final version 2.0.7316.34247, January 2020	Part of the actively maintained CrystalDisk family (CrystalDiskMark 9.0.3, May 2026)
Best for	Answering “how fast is it?” and comparing drives by score	Answering “is it okay?” — ongoing health, temperature and wear watch

Using them together: the two-question routine

Every drive check should ask both questions, in this order. First, health: open CrystalDiskInfo and read the status and temperature. If the status is anything other than good, stop testing, back up or clone the drive, and treat performance as irrelevant until your data is safe. Second, performance: run AS SSD Benchmark and compare the result with the drive’s class and with your own earlier results. Low scores with good health point to configuration — alignment and controller mode are shown in AS SSD’s own window — or to a drive that is full or simply slow by design. Good scores with declining health point to replacement planning, not celebration. Records matter: save the AS SSD screenshot and note the health figures on the same date, and a trend over months becomes visible, which is worth more than any single reading.

Two scenarios that show why both matter

Consider a drive that benchmarks beautifully — strong sequential figures, a healthy total score — while its SMART data shows a rising error count and a health status that has slipped from good to caution. Trust the health data: back up immediately, because the benchmark has only proved the drive was fast on the day it may be preparing to fail. Now consider the opposite: SMART reports perfect health, yet AS SSD scores are half what the drive’s class should produce, and its window shows a partition-alignment warning. Trust the benchmark: the drive is not dying, it is misconfigured, and fixing the configuration is free. Neither tool alone could have reached the right conclusion in both cases, and applying the wrong tool’s verdict — celebrating the first drive’s speed or replacing the second drive outright — wastes either data or money. That is the whole argument of this page in miniature: speed and health are separate facts about a drive, each tool reports one of them faithfully, and a complete check always asks for both.

Verdict by scenario

“How fast is my SSD?” AS SSD Benchmark. “Is my SSD healthy, hot or worn?” CrystalDiskInfo — AS SSD cannot answer at all. “My system feels wrong and I don’t know why”: CrystalDiskInfo first for safety, AS SSD second for speed, in that order. The pair costs nothing, takes minutes, and together they cover the two questions every drive owner actually has. Neither replaces the other, and using only one leaves exactly half the picture blank.

Get AS SSD from the download page, and see where both tools sit in the full landscape in our best SSD benchmark tools overview.

Best SSD Benchmark Tools: Which One to Use for Each Job

“What is the best SSD benchmark?” is the wrong question, because the tools do different jobs. One gives you a single comparable score, one gives you configurable raw speed tests, one reads drive health instead of speed, one is the vendor’s own transfer-size sweep, and one serves a completely different operating system. This overview sorts the major tools by the job each does best, so you can pick by need instead of by habit. Every Windows tool mentioned here is free or has a free tier, and our own focus tool, AS SSD Benchmark, is on the download page.

The tools at a glance

AS SSD Benchmark — the total score. A Windows freeware classic (final version 2.0.7316.34247, January 2020) that measures sequential, 4K, 4K-64Thrd and access time, adds Copy and Compression tests, and compresses everything into a Read/Write/Total score with a simplified formula. Pick it when you want one comparable number and the alignment and controller display in its window.

CrystalDiskMark — the general-purpose standard. Actively maintained (9.0.3, 24 May 2026), free under the MIT licence, built on Microsoft DiskSpd, and configurable in queues and threads. Pick it for a current, flexible speed check; see AS SSD Benchmark vs CrystalDiskMark for how its results relate to AS SSD’s.

CrystalDiskInfo — the health monitor. Not a benchmark at all: it reads SMART data and reports health status, temperature and wear indicators. Pick it whenever the question is “is my drive okay?” rather than “how fast is it?” — the division of labour is explained in AS SSD Benchmark vs CrystalDiskInfo.

ATTO Disk Benchmark — the vendor sweep. Freeware from ATTO Technology (official download via a form), measuring sequential throughput across transfer sizes from 512 B to 64 MB. Pick it to verify peak sequential performance and scaling, the way manufacturers do.

HD Tune Pro — the diagnostic suite. A paid tool after a 15-day trial (version 6.10), combining a basic benchmark with SMART health, error scanning and utilities. Pick it when a drive is suspect and you need a surface scan, not just a score.

Blackmagic Disk Speed Test — the Mac answer. Free from Blackmagic Design, testing disks in video terms: which formats and frame rates a disk sustains. Pick it on macOS, where AS SSD does not exist — see SSD benchmark tools for Mac. Two further names complete the picture: Anvil’s Storage Utilities, an old enthusiast tool with configurable data compressibility and an endurance mode, and UserBenchmark, a whole-PC crowdsourced percentile service — both compared in their own pages in this cluster.

Comparison table

Dimension	For a total score: AS SSD Benchmark	For general speed: CrystalDiskMark	For health: CrystalDiskInfo
What it measures	Seq, 4K, 4K-64Thrd, access time, Copy and Compression	Sequential and random tests via DiskSpd, configurable queues/threads	Measures nothing — reads SMART health, temperature and wear data
Score / result form	MB/s or IOPS plus a weighted Total score	MB/s and IOPS per test; no total score	Health status and SMART attribute values
Platform	Windows only; portable	Windows	Windows
Licence and price	Freeware; free	Free; MIT licence	Free (from the Crystal Dew World project family)
Maintenance status	Final version January 2020	Active; 9.0.3, May 2026	Part of the actively maintained CrystalDisk family
Best for	Ranking drives by one score; copy/compression behaviour; alignment checks	Everyday speed verification with current settings	Ongoing health watch: temperature, wear, SMART warnings

A sensible minimal toolkit

Most users need exactly three of these: one benchmark for a comparable score (AS SSD), one current general benchmark (CrystalDiskMark), and one health monitor (CrystalDiskInfo) left running or checked monthly. Add ATTO if you validate hardware, HD Tune Pro if you rescue suspect drives, and Blackmagic if a Mac joins the household. Whatever you install, follow three rules: compare results only within the same tool and settings; record the tool version and test size with every result; and never let a speed score stand in for a health check. If your benchmark says a drive is slow and you decide to replace it, our notes on choosing a new NVMe SSD translate scores into a shortlist.

How to run any of these tools properly

Whichever tools you choose, technique decides whether the results mean anything. Let the system idle before you start, close downloads, game launchers and sync clients, and keep the drive’s free space and temperature in a normal state — a nearly full or overheating SSD will benchmark below its true ability in every tool on this page. Run each test more than once and treat the consistent figure, not the best figure, as the result. Record the essentials with every saved result: tool name and version, test size and settings, drive model and firmware, and how full the drive was. Compare only results gathered the same way, and be suspicious of any conclusion built on a single run of a single tool. Finally, sequence your checks sensibly: health first if a drive is suspect, speed second, and buying decisions last, based on both. Followed consistently, these habits make a handful of free tools more trustworthy than a shelf of paid ones used carelessly — the tools differ, but honest measurement is a method, not a product.

One last selection rule covers the tools not given their own section above. Specialist utilities such as Anvil’s Storage Utilities belong in the kit when a specific feature — in its case configurable data compressibility and an endurance mode — is the thing your test actually needs, and whole-PC services such as UserBenchmark belong at the very start of investigating an unfamiliar machine, before you know which component deserves a dedicated tool. Neither replaces the core three; they extend it at the edges, for configurable experiments and first-glance triage respectively. Judge every addition to your toolkit by that standard: a tool earns its place by answering a question your current tools cannot, not by producing yet another number for a question already answered.

Verdict by scenario

One number to compare drives: AS SSD Benchmark. Quick modern speed test: CrystalDiskMark. “Is my drive dying?”: CrystalDiskInfo first, HD Tune Pro’s scan if suspicion remains. Vendor-style sequential validation: ATTO. Mac: Blackmagic. The best toolkit is the smallest one that covers speed, score and health — and now you know which tool covers which.

Start building yours from the download page.

SSD Benchmark for Mac: What to Use When AS SSD Benchmark Is Windows-Only

Let us start with the honest answer this page exists to give: there is no AS SSD Benchmark for Mac. AS SSD Benchmark is a Windows-only program — its final version, 2.0.7316.34247 from January 2020, runs on Windows, is portable, and has no macOS, Linux or online edition. Any website offering an “AS SSD Benchmark for Mac download” is not offering a real product. The good news is that Mac users are not left without tools: the Mac has its own established disk speed test, and this page explains what it does, how its results relate (and do not relate) to AS SSD scores, and how to think about storage testing on macOS. If you also use a Windows PC, AS SSD itself is on our download page.

The Mac tool: Blackmagic Disk Speed Test

Blackmagic Disk Speed Test, from Blackmagic Design, is the standard free disk benchmark on macOS, available free from the Mac App Store and also bundled with Blackmagic’s Desktop Video software. It comes from the professional video world, and it shows: instead of benchmarking in the abstract, it writes and reads video-sized data and answers the two questions a video user actually asks. Its “Will it Work?” panel lists video formats and frame rates and marks which ones your disk can sustain, and its “How Fast?” panel shows the read and write frame rates behind that verdict. A plain pair of read/write speed figures sits alongside for everyone else.

That video-first design is both its strength and its limit. If you edit video, it translates storage performance into your working language directly — no interpretation needed. If you are diagnosing why a Mac feels slow, it tells you much less: it is oriented to large sequential transfers, because that is what video is, and it does not give you the 4K random results, access times or weighted total score that AS SSD produces on Windows. It is not a Mac version of AS SSD, it is not made by the same author, and the two tools share nothing except the broad job of timing a disk.

Why you cannot convert the results

Because the tools measure different workloads, there is no conversion between a Blackmagic result and an AS SSD score — the same warning that applies between any two benchmarks, stated in detail in AS SSD Benchmark vs CrystalDiskMark, applies with extra force across operating systems. A Mac’s internal SSD showing a large Blackmagic write figure tells you its sequential write speed under that test. It says nothing about what AS SSD would report for 4K random performance, and AS SSD cannot run natively on the Mac to find out. Compare Blackmagic results with other Blackmagic results, on similar settings, and treat any site that publishes an “equivalent AS SSD score” for a Mac as inventing numbers.

Side-by-side comparison

Dimension	AS SSD Benchmark	Blackmagic Disk Speed Test
What it measures	Seq, 4K, 4K-64Thrd, access time, Copy and Compression tests on Windows	Disk read/write using video-frame-sized data, reported as speeds plus video format and frame-rate capability panels
Score / result form	Per-test MB/s or IOPS and a weighted Total score	Read/write speeds, “Will it Work?” format checklist and “How Fast?” frame-rate table; no total score
Platform	Windows only — no Mac version exists	macOS (the Mac-side tool in this comparison)
Licence and price	Freeware by Alexej Schepeljanski; free	Free from Blackmagic Design, via the Mac App Store and Desktop Video
Maintenance status	Final version 2.0.7316.34247, January 2020	Distributed and maintained by Blackmagic Design as part of its video software line
Best for	Windows users needing a full SSD performance picture and total score	Mac users — especially video editors — checking whether a disk sustains their formats

Practical advice for Mac owners

Use Blackmagic Disk Speed Test for what it is: a fast check of an internal or external disk’s throughput, and an authoritative answer for video work. Run it against external drives before committing them to a project — a drive that cannot sustain your format will drop frames no matter what its packaging claimed. For health questions (wear, errors, SMART status), remember neither tool family is a health monitor; on Windows that gap is covered in AS SSD Benchmark vs CrystalDiskInfo, and on a Mac you should look for a SMART-reading utility rather than a benchmark. And if a workflow spans both platforms — an external SSD shuttling between a Mac and a Windows PC — benchmark it on each side with that side’s tool and keep both records, rather than forcing one number to speak for both.

One safety note, plainly: do not download anything advertised as AS SSD Benchmark for Mac, macOS or “online”. No such edition exists, so such offers are at best mislabelled other software and at worst a lure. The real AS SSD is a small Windows ZIP from the official site, linked from our download page, with a published SHA-256 hash you can verify.

What about running Windows tools on a Mac?

Technically minded readers sometimes ask whether AS SSD Benchmark can be run inside a Windows virtual machine or compatibility layer on a Mac. Even where such setups launch the program, the result would not be a measurement of the Mac’s internal SSD in any meaningful sense: the virtualisation layer sits between the test and the hardware, the drive the program sees is a virtual device, and the numbers describe that stack rather than the physical disk. The same caution applies to benchmarking an external drive through layers of adapters and virtualisation — each layer changes what is being timed. If you need a figure for your Mac’s storage, measure it natively with the Mac tool described above. If you need an AS SSD score for a specific drive, run AS SSD natively on a Windows PC with the drive attached directly. Shortcuts that blur which hardware produced a number produce numbers that cannot be compared with anything — the one outcome worse than having no benchmark at all.

Verdict by scenario

Mac, video work: Blackmagic Disk Speed Test — it answers in formats and frame rates. Mac, general disk check: Blackmagic for throughput, plus a SMART utility for health. Windows: AS SSD Benchmark, as ever. There is no cross-platform winner because there is no cross-platform contest: each tool is the native answer on its own system.

For the complete map of which tool does which job, see the best SSD benchmark tools overview.

AS SSD Benchmark vs Anvil’s Storage Utilities: Two Classic SSD Tools Compared

AS SSD Benchmark and Anvil’s Storage Utilities belong to the same generation of enthusiast SSD tools, and many review archives from the last decade contain results from both. They overlap on the basics — sequential and random testing with a summary score — but each has a signature feature the other lacks: Anvil’s offers selectable data compressibility and an Endurance mode designed to write a drive toward exhaustion, while AS SSD offers its Copy-Benchmark scenarios and Compression-Benchmark graph. This page compares the two classics honestly, including the fact that both are old. AS SSD is on our download page.

What Anvil’s Storage Utilities does

Anvil’s Storage Utilities was built by an enthusiast for enthusiasts, and it shows in the options. Beyond standard sequential and random tests, it lets you choose the compressibility of the test data — fully compressible, partially compressible or incompressible — and run threaded IO tests. That compressibility control matters because some SSD controllers accelerate compressible data, so a benchmark that only writes easy data can flatter them. Anvil’s made the data pattern an explicit variable instead of a hidden one, which is why reviewers kept version 1.1.0 in their test suites for years.

Its most distinctive feature is the Endurance mode: a test designed to keep writing to a drive continuously, the kind of punishing workload used to explore how a drive behaves as it accumulates writes. That is a specialist tool. Endurance running consumes drive lifespan by design, so it belongs on test-bench drives, not on the only disk holding your data. The software spent much of its life in beta and release-candidate form, and version 1.1.0 is the one the review record settled on; like AS SSD, it is best understood as a finished-era tool rather than a living project.

What AS SSD Benchmark does

AS SSD Benchmark takes the opposite design approach: fewer knobs, fixed definitions. Its synthetic tests — sequential, 4K, 4K-64Thrd and access time — run without the operating system cache on a 1 GB test file by default, and its simplified score (Read = Seq × 0.1 + 4K + 4K-64Thrd, likewise for Write) gives every drive a comparable total. Where Anvil’s exposes compressibility as a setting, AS SSD exposes it as a measurement: the Compression-Benchmark graphs throughput across the compressibility range in one run, so you can see a controller’s dependence on data pattern instead of sampling it one setting at a time.

AS SSD’s other signature is the Copy-Benchmark, which times three realistic transfers — ISO, Program and Game folders — using the operating system’s copy functions, caching included, because that is how real copies behave. Together with the drive information, controller driver and alignment status shown at the top of its window, AS SSD works as a quick everyday check: run it, screenshot it, compare it with the large public record of identical runs. Anvil’s, by contrast, rewards users who want to configure the test itself.

Side-by-side comparison

Dimension	AS SSD Benchmark	Anvil’s Storage Utilities
What it measures	Seq, 4K, 4K-64Thrd, access time; Copy scenarios and a Compression graph	Sequential and random tests with selectable data compressibility and threaded IO; Endurance write mode
Score / result form	Per-test MB/s or IOPS plus Read, Write and Total scores from a simplified formula	Per-test results and a summary score for the chosen test configuration
Platform	Windows only; portable	Windows
Licence and price	Freeware by Alexej Schepeljanski; free	Free enthusiast utility
Maintenance status	Final version 2.0.7316.34247, January 2020	Version 1.1.0 is the widely used release; long beta/RC history, now essentially unmaintained
Best for	A standard, comparable score, copy behaviour and compression profile in one quick run	Configurable test data compressibility, threaded IO exploration and specialist endurance testing

Compressibility: setting vs graph

The compressibility difference deserves one more paragraph because it decides real purchases on older controller designs. With Anvil’s, you pick a data pattern and get the speed for that pattern — precise, but you need several runs to see the whole picture. With AS SSD’s Compression-Benchmark, one run draws the curve from compressible to incompressible, which makes a pattern-dependent controller obvious at a glance. Neither approach changes the underlying truth; they present it differently. If you are reproducing a specific published test, use the same tool and settings as the source; results across the two are no more interchangeable than any other pair of benchmarks, a point we develop in AS SSD Benchmark vs CrystalDiskMark.

Reproducing old results today

Because both tools are frozen in time, their results have an unusual virtue: comparability with the historical record. A review from the late 2010s that published AS SSD and Anvil’s figures can be re-run today, setting for setting, and the numbers should land in the same territory on the same hardware. That is genuinely useful when you are evaluating an older drive second-hand, following an archived tuning guide, or checking whether a firmware change altered behaviour that reviews documented years ago. The discipline required is to match the configuration exactly: Anvil’s compressibility and thread settings change its results materially, and AS SSD’s test size changes its results too, so note both alongside any figure you publish. Where a modern, maintained tool is required instead — for a brand-new drive on a current system — our comparison with CrystalDiskMark covers the actively developed alternative. The classics earn their place by continuity, not by novelty.

Verdict by scenario

Everyday check of a system drive: AS SSD Benchmark — faster to run, easier to compare, and its copy and alignment information is immediately practical. Investigating how a controller treats compressible data, or running controlled threaded-IO experiments: Anvil’s, in the hands of a user who knows which settings they changed. Endurance exploration: Anvil’s is the only one of the two with such a mode — on a sacrificial test drive only, with backups of anything that matters elsewhere. For most readers, AS SSD is the default and Anvil’s is the specialist drawer in the same toolbox; our best SSD benchmark tools overview places both in the wider landscape.

Get the standard tool first from our download page, and keep Anvil’s in mind when a test needs configuring rather than just running.

AS SSD Benchmark vs UserBenchmark: Single-Drive Depth vs Whole-PC Percentiles

AS SSD Benchmark and UserBenchmark are both called “benchmarks”, but they answer unrelated questions. AS SSD Benchmark spends all of its time on one drive and reports exactly what that drive did. UserBenchmark runs a short suite across your whole PC — CPU, GPU, storage and memory — and tells you how each component compares with other people’s identical components in its crowdsourced database. This page explains the difference, and states plainly where UserBenchmark stands with the enthusiast community, so you can decide how much weight to give each result. AS SSD itself is available on our download page.

Two different units of analysis

An AS SSD run produces measurements: sequential throughput, 4K and 4K-64Thrd random throughput, access time, copy-test times and a compression graph, summarised in a total score computed from those measurements with a simplified formula. The numbers describe your drive, on your system, today, and another user with the same drive can reproduce the same test and compare directly.

A UserBenchmark run produces a ranking. After testing your components, it compares each one against the distribution of results submitted by other owners of the same model and reports a percentile — your drive performed better than a certain share of submitted results for that model. That is useful for spotting a grossly underperforming component in a new build, but it is a relative statement about a self-selected sample, not a measurement of the drive itself. Percentiles also move as the database changes, even if your hardware never does.

The community-standing question, stated factually

Any honest comparison has to mention how UserBenchmark is treated by the communities that discuss PC hardware most. Links to UserBenchmark have been banned from being cited in several large Reddit communities, including r/hardware and r/Intel, following long-running disputes about how its aggregate scores weight different components and workloads. That is a documented community decision, and it is the reason you will often see a UserBenchmark result challenged or removed in enthusiast forums while an AS SSD or CrystalDiskMark screenshot is accepted without comment.

We state that as context, not as a verdict on every number the site produces. A percentile for your exact drive model can still be a quick sanity check. The practical lesson is narrower: if you need a storage result that other people will accept, reproduce and compare — for a support thread, a review, a warranty discussion or a buying decision — a direct measurement from a dedicated tool travels better than a crowdsourced percentile. And an aggregate whole-PC score should never be used to conclude that one specific SSD is faster than another, because the aggregate blends in weightings that have nothing to do with your drive.

Depth on one drive

For storage questions, depth beats breadth. AS SSD’s separation of sequential, 4K and 64-thread results tells you how a drive is fast or slow: strong sequential with weak 4K suggests a drive fine for file storage but sluggish as a system disk; a collapse in 4K write with normal reads suggests a full or heavily fragmented working set, a caching problem or a drive near its limits. The Copy-Benchmark’s ISO, Program and Game scenarios and the Compression-Benchmark add workload shapes that a single quick suite cannot represent. AS SSD also displays controller mode and partition alignment in its main window — two configuration faults that a percentile might hint at (“your drive is in the bottom range for its model”) without ever identifying.

Side-by-side comparison

Dimension	AS SSD Benchmark	UserBenchmark
What it measures	One drive in depth: Seq, 4K, 4K-64Thrd, access time, Copy and Compression tests	Whole PC briefly: CPU, GPU, SSD/HDD and RAM in one suite
Score / result form	Measured MB/s and IOPS per test plus a weighted Total score for the drive	Percentile ranking of each component against crowdsourced results for the same model
Platform	Windows only; portable, runs locally	Windows test program whose results depend on its online database
Licence and price	Freeware by Alexej Schepeljanski; free	Free to run; results live on the UserBenchmark service
Maintenance status	Final version 2.0.7316.34247, January 2020; results remain comparable across years	Ongoing online service; database and percentiles change over time
Best for	Answering storage questions precisely and producing results others can reproduce	A first-glance check that no component in a new build is drastically underperforming its peers

Which result should you quote?

Quote the tool that matches the question. “Is my PC broadly healthy?” is a whole-system question where a percentile sweep is a reasonable starting point. “Is this SSD performing as it should?”, “Did the new firmware help?”, “Why does Windows feel slow on this drive?” — those are storage questions, and they deserve storage measurements. For the head-to-head most readers actually need, see AS SSD Benchmark vs CrystalDiskMark, and for the full toolkit, the best SSD benchmark tools overview.

What a percentile can and cannot tell you about storage

A percentile for your drive model says your unit performed better than a stated share of submitted units. That can expose a genuinely faulty sample or a badly configured machine. What it cannot do is separate the drive from the system around it: the submitted results for any model mix together different motherboards, ports, drivers, firmware versions, fill levels and thermal conditions, so a mid-pack percentile may describe your setup rather than your SSD. It also cannot be archived meaningfully — the same unchanged PC can drift in percentile as new submissions arrive. A stored AS SSD screenshot, by contrast, freezes the actual measurements: when your drive slows down six months later, you can rerun the identical test and compare megabytes per second, not just a moving rank. For storage, where the interesting questions are “how fast, at what, and has it changed?”, measured values age far better than rankings, which is the deeper reason dedicated benchmarks remain the reference in storage discussions.

Verdict by scenario

New build, quick overall sanity check: a whole-PC sweep is convenient — then follow up any flagged component with a dedicated tool. Any conclusion about an SSD itself: AS SSD Benchmark (or CrystalDiskMark), measured directly. Posting results for a community to judge: use a dedicated benchmark, keeping in mind that several major communities do not accept UserBenchmark citations. Depth on the component you care about beats a blended ranking, every time the question is specific.

Run the dedicated test yourself: the official AS SSD file is on our download page.

AS SSD Benchmark vs HD Tune: Pure Benchmark vs Diagnostic Suite

People often ask whether they should use AS SSD Benchmark or HD Tune, as if one replaced the other. In practice they barely overlap. AS SSD Benchmark answers one question — how fast is this drive on defined workloads? HD Tune, especially HD Tune Pro, is a diagnostic suite that also happens to benchmark: its real territory is SMART health data, error scanning and drive utilities. This page draws the boundary clearly, so you use each tool for the job it actually does. AS SSD itself is on our download page.

What AS SSD Benchmark does — and stops there

AS SSD Benchmark runs six synthetic tests and three copy tests: sequential, 4K and 4K-64Thrd transfers, access time, a compression test, and timed copies of ISO, Program and Game file sets. Its synthetic tests bypass the operating system cache, its test file is 1 GB by default, and it summarises results as Read, Write and Total scores using a simplified weighted formula. The window also shows the drive model, firmware, controller driver and whether the partition alignment is correct — genuinely useful configuration clues, and the limit of its diagnostic ambition.

That is where it ends. AS SSD Benchmark does not read SMART attributes, does not report temperature, does not estimate remaining lifespan, does not scan the surface for errors, does not update firmware and does not securely erase a drive. If a result looks wrong, AS SSD can tell you the drive is slow or misaligned, but it cannot tell you the drive is failing. Treating a good AS SSD score as proof of drive health is the most common mistake new users make with it.

What HD Tune adds

HD Tune Pro, from EFD Software, is built around the health side of storage. Its benchmark measures transfer rate across the drive, access time and burst behaviour, but its distinguishing features sit in the other tabs: a Health view that reads and interprets SMART attributes, an Error Scan that checks the surface block by block for damaged areas, and utility functions such as secure erasing. For a drive that is making noises, throwing errors, disappearing intermittently or suspected of wearing out, those are the tools that matter — no benchmark score can substitute for a SMART report and a clean (or revealing) error scan.

The trade-offs are age and price. The free HD Tune 2.55 edition is very old, and the current product is HD Tune Pro 6.10, offered as a 15-day trial after which a licence is required. Its benchmark also predates the NVMe era in design: it will happily measure a modern SSD, but its transfer-rate graph was conceived for spinning disks whose speed falls across the platter, so interpret its benchmark as a rough check rather than a precision SSD measurement. For pure SSD speed testing, AS SSD’s 4K and 64-thread tests and total score remain the more informative design.

Side-by-side comparison

Dimension	AS SSD Benchmark	HD Tune / HD Tune Pro
What it measures	SSD performance: Seq, 4K, 4K-64Thrd, access time, Copy and Compression tests	Transfer-rate benchmark plus SMART health, error scanning and drive utilities
Score / result form	Per-test MB/s or IOPS and a weighted Total score; results exportable	Transfer graph, SMART attribute table and health verdict, scan map of good and damaged blocks
Platform	Windows only; portable	Windows
Licence and price	Freeware by Alexej Schepeljanski; free	HD Tune Pro 6.10: 15-day trial, then paid; the basic free edition is the old 2.55
Maintenance status	Final version 2.0.7316.34247, January 2020	Pro line current at 6.10; free edition long unchanged
Best for	Measuring and comparing SSD speed, checking alignment and controller mode	Checking whether a drive is healthy: SMART status, surface errors, pre-disposal erasing

A practical workflow that uses both

When a system slows down, order matters. First check health: a SMART view such as HD Tune Pro’s Health tab (or a free monitor such as CrystalDiskInfo, covered in AS SSD Benchmark vs CrystalDiskInfo) will flag a failing drive in seconds, and a failing drive should be backed up or cloned — see our guide to cloning your OS drive to an SSD — before you spend time benchmarking it. If health looks fine, run AS SSD Benchmark: low scores with a “BAD” alignment or an IDE-mode controller note point to configuration, while low scores with everything correct point to a drive that is full, hot or simply outclassed. Finally, an error scan is the tie-breaker when symptoms persist despite good health indicators and normal scores.

Which one should a beginner install first?

Start with AS SSD Benchmark, for three practical reasons. It is free with no trial clock, it is portable so there is nothing to install or remove, and its single window answers the question beginners actually arrive with — “is my SSD fast, and is anything obviously misconfigured?” — including the alignment and controller-mode display that catches the most common setup faults. Add a health tool as the second step, not the fifth: the free option most Windows users pair with AS SSD is CrystalDiskInfo, which covers SMART status and temperature, while HD Tune Pro earns its licence fee when you need its error scan on a drive you already suspect. That ordering — speed tool first because it is simplest, health tool immediately after because scores prove nothing about survival — gives a beginner complete coverage without paying for a diagnostic suite they may never need. What matters is that both halves get covered; which brand supplies the health half is a secondary choice.

Verdict by scenario

“How fast is my SSD?” AS SSD Benchmark. “Is my drive dying?” HD Tune Pro’s health and scan tools — AS SSD cannot answer that question at all. “My PC is slow and I don’t know why”: health first, benchmark second, in that order. The tools are complements, not rivals, and the only wrong choice is expecting either one to do the other’s job.

Get AS SSD from the download page, and for the full division of labour across all the major utilities, see the best SSD benchmark tools overview.

AS SSD Benchmark vs ATTO Disk Benchmark: Two Different Views of Drive Speed

ATTO Disk Benchmark and AS SSD Benchmark are two of the oldest names in storage testing, but they look at a drive from opposite ends. ATTO sweeps sequential transfers across many block sizes and shows you a curve. AS SSD Benchmark concentrates on a small set of defined tests — sequential, 4K, 4K with 64 threads and access time — and rolls them into a total score. This page explains when each view is the useful one. You can download AS SSD Benchmark from this site; ATTO itself is distributed by its vendor, as explained below.

What ATTO does differently

ATTO Disk Benchmark comes from ATTO Technology, a company that builds storage connectivity products, and it is distributed as vendor freeware — the official download asks you to fill in a form, which is why many people first meet it through download mirrors instead. Its signature test measures sequential read and write throughput across a ladder of transfer sizes, from 512 bytes up to 64 MB. The resulting graph shows the point at which a drive reaches its full sequential speed: tiny transfers are slow on almost everything, throughput climbs as the transfer size grows, and then it levels off. That curve is exactly what a manufacturer or system builder wants when checking that a drive, controller and connection are performing as a combination.

Because the emphasis is sequential, ATTO is generous to drives. A modern SSD will usually show its most flattering numbers here, close to the headline speeds printed on the box, because retail packaging figures are also sequential. That does not make ATTO wrong — large file transfers, video capture and media work really are sequential workloads. It does mean an ATTO graph alone cannot tell you how a drive behaves as an operating-system drive, where small random reads and writes dominate.

What AS SSD Benchmark does differently

AS SSD Benchmark was written specifically for solid-state drives. Its synthetic tests do not use the operating system cache, and alongside its sequential row it measures random 4K performance twice: once in the ordinary single-threaded pattern and once spread across 64 threads, which exposes how a drive and its controller handle queued commands. It also records access time, and its simplified score — Read = Seq × 0.1 + 4K + 4K-64Thrd, and the same for Write — deliberately weights the random results far more heavily than the sequential one. A drive can therefore look ordinary in AS SSD while looking spectacular in ATTO, and for a Windows system drive the AS SSD view is usually the more honest predictor of how responsive the machine will feel.

AS SSD adds two practical extras. The Copy-Benchmark times ISO, Program and Game copy scenarios using the operating system’s own copy functions, and the Compression-Benchmark charts performance against data compressibility. The main window also shows the controller driver and partition alignment status, so a single run can reveal a misconfigured system, not just a slow drive. None of that appears in an ATTO graph.

Side-by-side comparison

Dimension	AS SSD Benchmark	ATTO Disk Benchmark
What it measures	Seq, 4K, 4K-64Thrd and access time, plus Copy and Compression tests	Sequential read and write across transfer sizes from 512 B to 64 MB
Score / result form	Per-test MB/s or IOPS plus Read, Write and Total scores	Throughput curve by transfer size; no total score
Platform	Windows only; portable	Windows (vendor distribution)
Licence and price	Freeware by Alexej Schepeljanski; free	Vendor freeware from ATTO Technology; free, official download requires completing a form
Maintenance status	Final version 2.0.7316.34247, January 2020	Long-running vendor tool; widely mirrored versions date from the late 2010s onward
Best for	Judging a drive as a system disk: random performance, total score, copy behaviour, alignment	Checking peak sequential throughput and how throughput scales with transfer size; vendor and builder validation

Reading the two results together

A healthy drive tells a consistent story in both tools: ATTO’s curve climbs quickly and flattens near the drive’s sequential ceiling, while AS SSD’s sequential row lands in a similar range and its 4K rows show the random performance underneath. Warning signs are mismatches. If ATTO reaches full speed only at very large transfer sizes, small-file work will suffer. If AS SSD’s 4K write is far below what comparable drives achieve while sequential results are normal, look at alignment, controller mode and free space before blaming the hardware — AS SSD’s own header display is designed to surface exactly those configuration problems.

For a broader view of how the major tools divide the work, see our roundup of the best SSD benchmark tools and the head-to-head AS SSD Benchmark vs CrystalDiskMark, which covers the other tool most people pair with ATTO.

Common mistakes when comparing the two

The most frequent error is quoting ATTO’s peak sequential figure as if it were the drive’s everyday speed. That number is real, but it describes large, queued sequential transfers — the easiest work a drive ever does. Everyday Windows use is dominated by small reads and writes scattered across the disk, which is why AS SSD weights its 4K results so heavily in its score. A second mistake is comparing results gathered at different queue settings or test lengths and treating a small difference as meaningful; run both tools back to back on an idle system, with the drive in the same state, before drawing any conclusion. A third mistake is ignoring the system around the drive: the same SSD will post different numbers behind a slower controller, in a thermally cramped enclosure, or on a nearly full volume, in both tools. Benchmarks measure a drive in a system, never a drive in the abstract, and both ATTO and AS SSD are honest only when you keep that context attached to their results.

Verdict by scenario

Verifying a drive reaches its advertised sequential speed: ATTO. Choosing or troubleshooting a Windows system drive: AS SSD Benchmark, because 4K and 64-thread behaviour decide how the machine feels. Validating a build or a storage product: ATTO’s transfer-size curve, ideally with AS SSD as a second opinion. Used together they take minutes and describe both the ceiling and the foundations of a drive’s performance.

Start with the official AS SSD file on our download page — it is a small portable program, so you can run it alongside ATTO without installing anything.

AS SSD Benchmark vs CrystalDiskMark: Which SSD Test Should You Trust?

If you search for an SSD speed test, two names come up again and again: AS SSD Benchmark and CrystalDiskMark. They are both free, both small, both widely quoted in reviews — and their numbers cannot be swapped for each other. This page explains what each tool actually measures, how their test items line up, why the same drive produces different-looking results in each one, and how reviewers combine the two instead of picking a winner. If you only need the software itself, you can download AS SSD Benchmark first and run both tools side by side as you read.

The short answer

Use CrystalDiskMark when you want a current, actively maintained, general-purpose speed check with configurable queues and threads. Use AS SSD Benchmark when you want its specific combination of 4K and 64-thread results rolled into a single total score, plus its Copy and Compression tests and its alignment and controller display. Neither result is “the true speed” of your drive. Each is a defined workload, and a result only means something when you compare it with results from the same tool, the same test size, and similar settings.

How the test items correspond

The two tools overlap more than their layouts suggest. AS SSD Benchmark runs sequential read and write, random 4K read and write, 4K with 64 threads, and access time, using a 1 GB test file by default (1, 3, 5 or 10 GB can be selected) and without using the operating system cache for its synthetic tests. CrystalDiskMark, which is built on Microsoft DiskSpd, runs sequential tests and random 4K tests with queue and thread combinations you can configure. Roughly speaking, AS SSD’s Seq row corresponds to CrystalDiskMark’s sequential rows, AS SSD’s 4K row corresponds to a single-queue, single-thread random test, and the 4K-64Thrd row is a heavily queued random test — conceptually closer to CrystalDiskMark’s high-queue random presets, but not identical in block handling, timing or data pattern.

AS SSD Benchmark also adds two things CrystalDiskMark does not focus on. The Copy-Benchmark times three realistic copy scenarios — ISO (large files), Program (many small files) and Game (a mix) — using the operating system’s copy functions. The Compression-Benchmark shows how performance changes as data becomes more or less compressible, which matters on controllers whose speed depends on the data pattern. At the top of its window, AS SSD also shows the drive model, firmware, controller driver and partition alignment status, which is why it has long been a quick diagnostic as well as a benchmark.

Why the scores cannot be compared directly

AS SSD Benchmark collapses its results into Read, Write and Total scores. The simplified scoring formula is: Read score = Seq Read × 0.1 + 4K Read + 4K-64Thrd Read, with the same pattern for Write. That weighting deliberately makes small random transfers dominate the headline number. CrystalDiskMark does not produce a single score at all — it reports MB/s (and optionally IOPS) per test. So an AS SSD total of, say, a few thousand points and a CrystalDiskMark sequential figure of several thousand MB/s are not two estimates of the same thing. They are different units answering different questions.

Even the shared measurements differ underneath. The tools use different test engines, different default file sizes and different queue behaviour, so the same drive can show a higher sequential number in one tool and a stronger random result in the other. That is not a contradiction and it does not mean one tool is lying. It means you should never rank two drives where one was measured with AS SSD and the other with CrystalDiskMark, and you should never paste a CrystalDiskMark result into a thread asking for AS SSD scores. Compare like with like, and state the tool, version, test size and drive state whenever you publish a result.

Side-by-side comparison

Dimension	AS SSD Benchmark	CrystalDiskMark
What it measures	Seq, 4K, 4K-64Thrd, access time, plus Copy and Compression tests; shows alignment and controller status	Sequential and random 4K workloads based on Microsoft DiskSpd, with configurable queues and threads
Score / result form	MB/s or IOPS per row, plus Read, Write and Total scores using a simplified weighted formula	MB/s (and IOPS) per test; no single total score
Platform	Windows only; portable, no installation	Windows
Licence and price	Freeware by Alexej Schepeljanski; free to use	Free; MIT licence (per Wikipedia), by Noriyuki Miyazaki / Crystal Dew World
Maintenance status	Final version 2.0.7316.34247, January 2020; no newer release since	Actively maintained; version 9.0.3 released 24 May 2026
Best for	A single comparable total score, copy and compression behaviour, alignment checks, matching the large archive of published AS SSD results	A quick, current, configurable speed check and comparing drives tested with the same preset

How reviewers use both together

Review sites have paired these tools for years because they are strong in different places. CrystalDiskMark gives a fast, repeatable picture of peak sequential throughput and of random performance at chosen queue depths — useful for checking that a new drive reaches roughly the speeds its class should reach. AS SSD Benchmark adds the weighted total score that makes drives easy to rank within its own database of results, the Copy test that resembles moving real folders around, and the compression graph that can reveal controllers that slow down on incompressible data. Running both takes only a few minutes, and together they catch problems that either tool alone can miss — for example a drive with strong sequential numbers but weak 4K results, which will feel slow as a system drive despite an impressive headline figure.

A sensible routine for a new drive is: run CrystalDiskMark for a baseline, run AS SSD Benchmark for the total score and copy results, save a screenshot or export from each, and repeat the same pair after any firmware, driver or alignment change. If you are choosing a drive rather than testing one, read our overview of the best SSD benchmark tools for the wider toolkit, and see our notes on choosing an NVMe SSD for how benchmark results translate into a buying decision.

Verdict by scenario

Checking a brand-new drive quickly: CrystalDiskMark, because it is current and configurable. Comparing your result with years of published scores, or checking alignment: AS SSD Benchmark. Diagnosing why a system feels slow: run both — the 4K rows matter more than sequential peaks for everyday responsiveness. Publishing a result for others to verify: publish both, with tool versions and test sizes stated. There is no loser here; there are only results used inside or outside the context that makes them meaningful.

Ready to run the comparison yourself? Get the official file from our download page, and read the companion comparison AS SSD Benchmark vs CrystalDiskInfo to see why a benchmark still tells you nothing about drive health.