By Michael / Last Updated March 8, 2022

SSD runs slowly after clone in Windows 7/8/10/11

After upgrading a hard drive from HDD to SSD or migrating OS to SSD in Windows 7/8/10/11, you may have a headache when you see your computer works in a speed you are not expecting: SSD boots even much more slowly than single HDD boots! Don’t be mad or panic!

Why does SSD boot more slowly after migrating OS from HDD to SSD?

The very reason for slow SSD boot is wrong partition alignment. Any direct OS migration is the process of copying everything from the old to the new. It completely ignores mechanical differences although there lie diversities between HDD and SSD. Thus, you’ll notice:

1) Installing Windows on SSD, no trouble.

2) Migrating OS from SSD to SSD, works fine.

3) However, when migrating OS from HDD to SSD, we see a tremendous speed drop in PC Startup!

It is because of misaligned partition in SSD: SSD starts 1st partition after 64 empty blocks, while HDD begins 1st partition after 63 blocks. Therefore, it takes time for computer to go through block to block to find the right file to load in SSD.

✍ Tips: Check if SSD partition is misaligned: Keystroke “Win” key + “R”, input “msinfo32”, go “Components > Storage > Disks”, find SSD. Divide the figure in “Partition Starting Offset” by 4096, if you get a fractional number, then SSD partition is misaligned. That’s the reason for slow SSD boot.


How to fix misaligned partition in SSD with 4K Alignment?

SSD adopts the smallest 4K sector to save data. If the 4K allocation units are not aligned in SSD, reading and writing will go across multiple sectors which causes SSD's poor performance. Thus, here comes AOMEI Partition Assistant Professional, a disk management tool that can do SSD 4k alignment easily and effectively. It works well with Windows 7/8/10/11; if you are running Windows Server, employ its Server edition.

✍ Note: It is available to download its demo version to have a try.

Download Freeware Win 10/8.1/8/7/XP
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Then, we need 5 steps to fix misaligned SSD partitions and speed up SSD performance.

Step 1. Launch the AOMEI product and enter the main interface. Then, select a partition from the SSD.

Step 2. Right-click the SSD partition, choose “Advanced” and “Partition Alignment”.

Partition Alignment

Step 3. In the new floating windows, we need to choose partition sector to align. In SSD optimization, we strongly recommend you to use “8 Sector” (usually we know it as SSD 4K alignment).

8 Sector

Step 4. After that, click on “OK” and “Apply” to run the software. When completed, this SSD partition is right aligned.

Apply Alignment

Step 5. Repeat the steps above to 4K align the rest partitions.

Wrap things up

It’s never complex to align SSD after clone once you find a proper tool. As mentioned in this post, AOMEI Partition Assistant Professional should be your best choice when it comes to 4K alignment. It’s user-friendly, ad-free, and easy to use, not to mention other useful features including SSD secure erase and schedule defrag. All these features are designed to make your PC work better.