SSD, AHCI and write performance

performancessdwindows 7

We've started to deploy SSD drives to our developers workstations. At this moment we're having the unpleasant surprise that the systems using the new SSDs often freeze, with the HDD activity led blinking or being continuously on.
Benchmarks shows read speeds around 180 MB/s, but write speeds around 5 MB/s.
All developers are using Windows 7 Enterprise, 64 bit, SP1.
The SSDs are Kingston SV200S3128G.
One of our developers suggested (based on his experience) the following sequence:

  • backup the workstation
  • use a tool to completely erase the SSD
  • make sure AHCI is enabled in BIOS
  • install Windows
  • restore from backup

So far, this procedure seems to work (we're still testing, but write speed seems to be 120 MB/s).
There are some questions in this context:

  • why do we have to completely reinstall Windows?
  • Is it possible to clean the SSD without reinstalling Windows? Is there a reliable tool?
  • If AHCI was disabled when Windows was installed and we enable it, shouldn't this be enough to correct the write performance issue?
  • If we have to completely erase the SSDs, does this mean the SSDs we've received were used before (SH)? I'm wondering this because the package I've got was open (I didn't think about it at that time, as I considered one of my coworkers simply took a peek inside the package).
  • Has anyone seen a similar problem before?

Best Answer

There are 3 things that come to mind. Firstly, what brand / model SSD are you using?? There have been some problems recently with controllers from certain manufactures. Secondly, Is TRIM enabled. Win7 will enable TIRM (if required) at installation time. So if the SSD was not present then, it may not be enabled. To check:

In an Elevated command Prompt windows, type the following:

fsutil behavior query disabledeletenotify
Results explained below:
DisableDeleteNotify = 1 (Windows TRIM commands are disabled)
DisableDeleteNotify = 0 (Windows TRIM commands are enabled)

Thirdly, Does the SSD have the correct sector alignment. To check the alignment of your SSD's partition:

In Windows, run msinfo32
click on: components -> storage -> disks

Look for your SSD and check the partition starting offset.

It needs to be divisible by 4096 otherwise the alignment is not correct.

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