SSD Alignment BAD in AS SSD Benchmark — Impact and Safe Ways to Fix It
Beside your drive name, AS SSD Benchmark may show the alignment status in red: BAD. Unlike a low score, this is not about how fast your SSD is today — it is about how its partitions line up with the drive’s internal layout, usually a leftover from an old clone or an install created in the hard-drive era. This guide covers what misalignment actually does, how to confirm it, and the honest, backup-first choice between trying to realign in place and starting clean.
Before you start: back up important files on the drive you are troubleshooting. Most checks below are read-only, but the fixes that touch BIOS settings, partitions or drivers should never be attempted without a current backup.
What alignment BAD means
SSDs store data internally in pages and blocks that are larger than the small units operating systems historically used. For reads and writes to land efficiently, the start of each partition should line up — be aligned — with those internal boundaries. Modern Windows installations align partitions correctly by default. A BAD result usually means the partition was created by older tooling, restored from an old hard-drive image, or cloned without alignment correction, so its starting offset falls in the wrong place. AS SSD Benchmark reports that offset status at the top of its window, alongside the drive model, firmware and controller information.
Notice what the warning does not say. It does not say the SSD is failing, worn out or about to lose data. Alignment is a layout property of the partitions, not a health measurement — and AS SSD Benchmark offers no SMART or health features with which to judge the drive itself. Keep the two questions separate: layout can almost always be corrected; health, if it is genuinely poor, is a different conversation.
What misalignment costs you
When a partition is misaligned, a single logical write can straddle two physical blocks, forcing the drive to do extra read-modify-write work behind the scenes. The visible effects are slower writes — small random writes suffer most — and more write amplification than necessary, which is wasted work for the controller. Sequential large-file results may look nearly normal, which is why some misaligned systems feel “mostly fine” while their 4K write numbers disappoint.
Be wary of any page that promises an exact percentage gain from fixing alignment. The improvement depends on the drive, the workload and how bad the offset is, and no honest guide can quote your number in advance. Use our alignment check walkthrough to record the before state, fix the layout if you choose to, and let your own re-run tell the story. If scores are low for several reasons at once, alignment is only one line in the fuller low-score checklist.
Confirm it before you fix it
Back up first — before confirmation steps that change nothing, and absolutely before any fix. A full backup of important files, ideally a complete drive image on a separate physical drive, is the price of admission for partition work. Then confirm the finding: re-run AS SSD Benchmark with the correct drive selected and note the exact offset/alignment line, and cross-check the partition starting offset in Windows’ system information or disk tools. If two views agree the partition is misaligned, you have a real target. If they disagree, resolve the disagreement before touching the layout.
Also record the companion facts while you are there: which controller label the header shows (a system can be misaligned and in IDE mode at the same time — see pciide – BAD), how full the drive is, and whether this Windows install is a fresh build or a clone from an old hard drive. Cloned-from-HDD installs are the classic alignment cases, and knowing the history helps you pick the fix below.
Your three honest options
Option one: leave it alone. If the machine is a secondary system, the drive is nearly full and due for replacement anyway, or the performance you have is acceptable for how the PC is used, living with misalignment is a defensible choice. It is a performance and efficiency issue, not a ticking bomb.
Option two: realign in place with a partition tool. Several partition utilities advertise alignment correction without a reinstall. That can work — but no tool can honestly promise a lossless outcome on your specific system. Power loss, a tool bug or an unexpected layout can damage the partition table, which is why the backup is not optional and why you should use a reputable tool, follow its own alignment workflow exactly, and never run it on a laptop battery that might die mid-operation. This site does not guarantee any tool’s result; if the data matters more than the downtime, choose option three.
Option three: clean reinstall or fresh clone with correct alignment. Back up, then install Windows fresh onto the SSD (letting the installer create the partitions guarantees modern alignment) or re-clone using a current cloning workflow that aligns partitions for SSDs. This is the most predictable path and the best moment to do it is when you were already planning a new drive or a clean start — see the workflow in cloning your OS drive to an SSD. It costs the most time and gives the cleanest result, with no in-place partition surgery to worry about afterwards.
After the fix: verify like a sceptic
Whichever path you took, verify rather than assume. Open AS SSD Benchmark — from the verified copy on our download page if you reinstalled — reselect the drive and confirm the header now shows alignment OK. Then run a clean full test with no other disk-heavy work running and the default 1 GB test size, and compare Seq, 4K and 4K-64Thrd against the numbers you recorded before. Writes and 4K writes are where an alignment fix most often shows itself.
If the header still says BAD, do not stack another tool on top of the first attempt. Restore from your backup if the system behaves oddly, and reconsider the clean-install path with fresh eyes. Two failed in-place attempts are information: the layout on that drive is not a good candidate for surgery.
When the real problem is the drive, not the layout
Occasionally alignment BAD is discovered on a drive that is also old, tiny by modern standards or showing unrelated errors in daily use. Fixing the layout will not restore worn flash or repair a failing controller. If Windows reports read errors, files corrupt, or the drive disappears intermittently, stop optimising: back up immediately, treat the drive as untrusted, and replace it. A correctly aligned new SSD, set up once with a clean install or aligned clone, leaves both problems behind. Alignment BAD on an otherwise healthy drive, though, is one of the most fixable findings in AS SSD Benchmark — confirm it, back up, pick the path that matches your risk tolerance, and verify the OK with your own eyes.