New
#190
As I was reading your last post, the first thought that came to mind was "flash your BIOS with a later ervision", but looking at the product info page (ASRock > Products > P55 Pro; this is your board right?), I see this in the list of connectors:
So I highly doubt that would be an issue....- 6 x SATAII 3.0 Gb/s connectors, support RAID (RAID 0, RAID 1, RAID 10, RAID 5 and Intel® Matrix Storage), NCQ, AHCI and Hot Plug functions
Other than that, I can't say I've tried running a drive with AHCI mode while it's restricted to SATA 1.5G/s speeds... If your drive has that jumper, I'd suggest taking it off regardless.
On that line of thought though, perhaps restricting the drive to SATA-I instead of SATA-II might be causing an issue? I can't say for sure though, and my Windows 7 PC is at home (I'm at work) so I can't test on mine to see if it is an issue.
By the way, what drives do you actually have connected at the moment? I'm not sure what you use, but I like using Speccy to get information on PC hardware.