Here you are (and thanks to the original poster elsewhere):
Re: How to enable AHCI/RAID mode without reinstalling windows (P35/ICH9/ICH9R)
--------------------------------------------------------------------------------
After reading through this thread, I began to think that enabling ICH10R RAID on an IDE installed OS would have been a nightmare, considering this would be for Windows 7 Beta. Oh the sheer simplicity, of it.
Here's some specs,
i7 965 EE
Asus Rampage II Extreme - bios 1001 - ICH10R
12Gb Corsair TR3X6G1600C8D @ 1600Mhz
2x EVGA GTX 295
1x WD3000HLFS 300Gb
OS - Windows 7 6.1.7000
This has been running for the most part stable and was setup using IDE enhanced in the BIOS under Sata Configured To
The addition is to be 4x WD1001FALS (4x 1Tb) to be run in RAID 5.
On adding the drives to the system and booting Windows without changing anything they are visible as 4 normal independant drives. Thats a start.
Going back to the BIOS and changing Sata Configured To to RAID, adding the 4 new drives to a RAID 5 array via the ROM option and booting resulted in the system rebooting during OS Startup (safe mode, normal, repair). hmmmm
The SOLUTION.
Changed the BIOS back to IDE Enhanced so Windows could boot.
In the Windows\System32\Drivers folder is a file called iaStorV.sys installed by OS by default.
Into the registry we go.
Navigate to:
HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\iaStorV
Change REG_DWORD "Start" from 3 to 0
Reboot
Go into the BIOS and change Sata Configured To to RAID
Windows should boot as normal, no lockups or BSOD's and you should see it installing Device Drivers followed by Device Installed Successfully.
I tested it prior to installing the Intel Storage Matrix v8.7.0.1007 (current as @ 18/2/09) and it worked fine.
I installed the Intel Storage Matrix software anyway to gain access to the Storage Console component and on reboot it worked just as good.
Long story short, ICH10R with Windows 7 required the modification of a single digit to enable RAID functionality right out of the box. No reg. keys, no copy/pastes, no prayers.
Anyway I think that wraps it up, try at your own risk and always backup first.