Raid-0 performance on Windows 8.1 Preview

today i upgraded to Windows 8.1
i noticed a performance drop of about 6% (AS SSD)
some has to be contributed not doing a secure erase + clean install
i was wondering what others had experienced.


Hello Jerome,

you are right and I made the same experience with Win8.1 (which I like very much).
Nevertheless we all should keep in mind, that the currently available Win8.1 version is a "Preview" and not a final product.
I am pretty sure, that the RTM version of the OS will have a better performance.


Trim on raid-0 works fine on Windows 8.1 with Z68 chipset.

With or without an especially modded Intel RAID ROM?

i only tested with modded raid orom (the last version you published for Z68)

Since I made the same experience, I have done a benchmark comparison between Win8 and Win8.1 under the exactly same conditions (2x256GB Samsung 840 PRO SSDs as RAID0 on a Z77 system with Intel EFI SataDriver v12.7.0.1936 and the Intel RAID driver v12.7.0.1036 WHQL).
You can see the benchmark results >here<.

New personal benchmark record after installing IRST drivers on Windows 8.1 Preview (4x Force GT 120Gb on sata-2):



12r mod Raid.jpg

my latest run on my Raid 840 Pro (120s) on the windows 8.1 preview edition (64)

Seems much the same as earlier versions.

3770k @ 4.7GHz 2x128GB Vertex4 W8.1

11.2 Driver

W81ASSSD.png Driver


Noooo… read score ‘666’ , +++ runaway…

I agree also with Jérôme current performance of Win8.1 x64 on the strictely same hardware, and same settings is about 6% less than we get with W7 x64 SP1.
Here are the 2 scores screens for W8.1 x64 Entreprise Preview:

as-ssd-bench Intel Raid 0 Vol 06.08.2013 15-59-50.png

Intel Raid 0 Volume_486GB_1GB-20130806-1604.png

Here are the 2 scores screens for W7 SP1 x64 Home:

as-ssd-bench Intel Raid 0 Vol 02.08.2013 17-50-47.png

Intel Raid 0 Volume SCSI Disk Device_512GB_1GB-20130803-1937.png

With my very similar hardware, but a different second OS (Wndows 8 x64) the differences are even more than 6%, but I do not really realize them while working.

Today i ordered an Haswell upgrade to my system:
Asus maximus vi formula.
So my 4 windows system ssd’s will run on sata3 ports instead of sata2.
Can’t wait to run as ssd benchmark lol.
Cheers Jerome.

We would like to see the results as well.
I have read somewhere, that the maximum performance will already been reached with 3 SSDs as RAID0 members. Then the Southbridge lanes may be the bottleneck.

Not that I would ever install a Micro confidential, but just say I installed the 8.1 9471.

The winsat return was nice, about the same read but went from a 302MB write to a 522.

Windows is installing the intel for the RST driver. Optimize still showing raid as a HDD until winsat is run, then you see SSD.

Still no TRIM. But GC is kicking in within a hour and giving the trim test to return trim working.

@ odiebugs:
Thanks for your info regarding the leaked Build 9471 of the upcoming Windows 8.1.

Yes, the upcoming Win8.1 will have 2 different Intel RAID drivers on board:

  1. an old Intel MSM RAID driver v8.6.2.1024 dated 08/09/2010, which is named iaStorV.sys and only usable with ICH6R, ICH7R and C600=X79 Chipsets, and
  2. a rather new Intel RST(e) driver (actually v12.0.1.1015 dated 07/12/2013), which is named iaStorAV.sys and designed for all DEV_2822 and DEV_282A Intel Express Chipset SATA RAID Controllers.

Note: Contrary to Win7 the Operating Systems Win8 and Win8.1 neither need nor use the SCSI filter driver named iaStorF.sys, which is part of all the Intel RST(e) driverpacks (from v11.5 up). The reason is, that Win8/Win8.1 do not only support the TRIM command, but additionally the UNMAP command, which can handle all drives as SCSI ones and makes the SCSI Filter driver dispensable.

Thanks, you must have known I was going to ask about the iastorav.sys.

I don’t know why, but if you remember on win 8 I have never had fast TRIM, mostly GC was kicking in. I ran some benches on the iastorav and had slow TRIM or GC, then I installed the, I have run optimize and I am getting TRIM in 5mins on the 1016, can’t believe it.

If the RTM 9471 doesn’t change much, this could be a really great OS, maybe even better then 7. Getting better benches then 7 also.

******** When I open your message there is nothing but blank page. I know you must have found the leak, but here is a place if anyone else wants it…

Do you mean my PM? Please try it once more. If you still should not be able to read it, I will send the content via eMail.

If anyone needs to enable net 3.5 in the new 9471.

I found that the command -" dism.exe /online /enable-feature /featurename:NetFX3 /Source:C:\sources\sxs " did NOT work. Where C is the install media location.

But using limit access after SXS, works and allows the 3.5 to work along with 4. I ran in powershell (ADMIN)

dism.exe /online /enable-feature /featurename:NetFX3 /Source:C:\sources\sxs /LimitAccess

Fern: Yes PM, when I opened it there was nothing, but as you will see I replied. Thanks.

This build seems to be great so far.