I have seen it mentioned several time in this forum that when running Windows 7, either MSAHCI.SYS or PCIIDE.SYS are supported drivers for Trim.
Unfortunately, I've not been able to find any documentation from Intel or Microsoft that says the same thing. I have found references to MSAHCI.SYS supporting Trim, but no references to PCIIDE.SYS. The Intel Solid State Drive Optimizer white paper specifically says that Microsoft AHCI storage drivers are needed for native Windows 7 support of Trim, and that all other cases require the SSD Toolbox.
Am I just missing the references to PCIIDE.SYS somewhere, or is it indeed not supported for Trim in Windows 7?
You pose a very good question. From searching the net everyone says that PCIIDE.SYS passes the "trim" command also, but i've seen nothing from Microsoft on this nor Intel. It would be nice if one or the other can confirm this. The WIN7 driver that was installed by defacto on my macbook pro when i installed win7 was PCIIDE.sys.
Using the PCIIDE.sys driver:
(1) Run Crystal Diskmark or similar to acquire benchmark A.
(2) Execute the Toolbox "Full Diagnostic Scan" to write a very large file to fill up the drive (upon completion, the scan marks the file for deletion).
(3) Wait ~one-half hour.
(4) Run Crystal to acquire benchmark B. You will see that benchmark B is similar to benchmark A, indicating that trim has erased blocks associated with the large file marked by the scan for deletion.
(5) If you have any doubts about the result, turn off trim in Win7 and repeat the above process to see a substantial difference between benchmark A and benchmark B.