jaquith :
When you get a chance I'd be interested how your RAID turned-out. My assumption is all went well!
So I finally took the plunge and delved into the BIOS RAID on my P55A-UD4 and I couldn't believe how smoothly it went.
The configuration I was aiming for was a single SATA2 HDD for OS+Apps, plus 2x SATA2 HDDs in RAID 0 for data. I connected the HDDs to the chipset Intel controller, the standalone HDD in port4 and the 2 RAID member HDDs (500GB each) in port0 and port1 (I also have an optical drive in port5). Like you say, it doesn't really matter which ports are used, but for organisational purposes I chose to keep the RAID members in adjacent ports.
In the BIOS Integrated Peripherals, I set the PCH SATA Control Mode to RAID(XHD), then save and exit the BIOS. After the BIOS POST, I accessed the RAID BIOS setup utility to configure a RAID array. This was done by following the onscreen instruction to press CTRL-I to enter Configuration Utility.
The main menu for the RAID configuration utility has the option to Create RAID Volume, and my three HDDs were listed in ports 0, 1 and 4, initially with status "Non-RAID Disk".
In the Create Volume menu, I selected the RAID level 0 (stripe) and selected just the two HDDs in ports 0 and 1 to be RAID members, leaving the default strip size 128MB and using up the full capacity of the drives (just under 1TB). Back in the main menu, the two HDDs in ports 0 and 1 then showed as "Member Disk", whilst the standalone HDD remained as "Non-RAID Disk".
On exiting the RAID configuration utility, I had Win7 Pro ready to install from the DVD drive. During Win7 installation, both the standalone HDD and the new RAID drive was presented as candidates for the target installation. I chose the standalone HDD and this did not require any additional RAID/AHCI drivers.
After Win7 had installed, the RAID drive was not visible in Windows Explorer, nor was it visible in the Storage Disk Management snap-in of the Computer Management Console. Only after installing the Gigabyte motherboard Intel SATA RAID driver was the RAID drive available under Win7.
And that was it! Thanks
jaquith for giving me the confidence to go forth and RAID.
Next I might have a play with the XHD feature