I got rid of my RAID problems, and as a nice bonus this also cured the audio feedback I got from the board during I/O.
I got 2 74Gb Raptors, set them up with XP Pro2 with updated RAID controller drivers. The old ones are going to be up for testing individually.
I did a quick bench with HD-Tach, which looks good enough to me. I also ran OCCT for 2 hours without a problem. I will of course play with it a bit more. I'm at the bios settings I was when I experienced most of my previous problems.
I guess I'm up for level 2 now