SSD Woes with msahci

So I have an Intel X25-M Gen 2 SSD originally installed on XP. I've since migrated to to 64-bit Windows 7 and set about optimizing this thing in several ways:

1. I wanted to perform a secure erase and after much grief, I managed that ;-)

2. I wanted to fix the alignment and after much more grief I managed that too. Great, I thought, I'll image that sucker. When I later restored that image I found that Paragon had undone my alignment. Sigh. So, I've developed a solution for that!

3. I wanted to use the optimum driver. The system is a Dell XPS 420 and I am not using RAID. The BIOS only provides for AUTO or RAID selections (no straight AHCI option).

By messing with the Registry, I've been able to boot Win 7 with the following drivers:

* pciide
* iaStorV
* iaStor (latest from Intel)

iaStorv gave the best performance but it doesn't support TRIM (as I understand it). The latest iaStor is supposed to support TRIM but it was significantly slower on simple reads (iaStorV: 247MB/s versus iaStor:186MB/s.

What I have not been able to do is make this darn box work with msahci. I have hacked the registry to disable the other drivers and forced Windows to load/use msahci. Part way through the boot, the machine blue screens and immediately reboots before I can catch even a tiny amount of the error message. Changing the BIOS between RAID and AUTO makes no difference. In RAID mode, I can load iaStor or iaStorV. In AUTO mode I can load pciide. But msahci (which is the one I really think I want) will not load in either mode.

Any thoughts or suggestions appreciated.

Thanks for the tip re: preventing auto reboot. Yes, it's the good old STOP 0x0000007B.

And yes, I've done the registry hacks. If I use that to force the loading of the msahci driver, it blue screens. So it seems that msahci itself is the problem (not the failure to enable that driver in the registry).

Maybe msahci is just not compatible with this motherboard/BIOS? I did read that some Asus boards with the X58 chipset also had problems with msahci.

You might have already tried this stuff but anyway...

AHCI is fully supported in Microsoft Windows Vista and the Linux operating system from kernel 2.6.19. Older operating systems like Windows XP require drivers written by the host bus adapter vendor in order to support AHCI. Windows XP requires the installation of a vendor-specific driver even if AHCI is present on the host bus adapter because Windows XP was released before Serial ATA was invented.
By default, MS Vista and 7 have the Msahci driver disabled.

So, how to enable AHCI if you already install Windows Vista/Windows 7 using IDE interface.

Solution…(Always back up the registry key prior to making changes)

1. Exit all Windows-based programs.
2. Click Start, type regedit in the Start Search box, and then press ENTER.
3. If you receive the User Account Control dialog box, click Continue.
4. Locate and then click the following registry subkey:

HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Msahci

5. In the right pane, right-click Start in the Name column, and then click Modify.
6. In the Value data box, type 0, and then click OK.
7. On the File menu, click Exit to close Registry Editor

Restart and go into the BIOS and make the changes from IDE to AHCI and restart and away you go.

Source: [Solved] Can't use ssd in AHCI mode-->Only in IDE - General-Storage - Storage

Sanvean said:

Hi Malch,
What version of iaStor do you have?
This is what I'm using which has TRIM:
My reads are 270mb

I was running 9.6.0.

Ahhh, but yours is actually newer than the "latest" on Intel's site. Hmmm, found the 9.6.2 and am downloading now. I will try this one later and see how it does.

[I think my MB/BIOS doesn't like msahci. It may also be related to some legendary problems with the eSATA port on the XPS 420.]

iaStor kills pciide on the 64-thread benchmarks. If this new version gives me 270MB reads + trim, I shall be a very happy camper

It looks like we have a winner. iaStore 9.6.2 is giving me 250MB reads. On all tests, it's giving me the best results I've seen. Plus TRIM.

I reckon this will be the best configuration for me. Hard to imagine that msahci will do much better. And since it's currently giving me 0.0MB, it's not an attractive option anyway.

Thank you Sanvean for the pointer.