The SATA RAID supplied by the chipset has proven to be such a pain that I have to vent here. I tried to use it on my Windows 7 Ultimate x64 to provide some redundancy, and eventually gave up after so many failures. The driver seemed to randomly put the array in rebuild, which slows the Core 2 Quad 9550 with 12 GB memory to a crawl. Sometimes a drive was just randomly reported as failed, the whole array as offline. Luckily enough most of the time the boot/system drive was a single Raptor, so Windows still survived. A measure for redundancy for my data turned into a constant live test for my backup strategy. ;)
If you search for Intel Matrix Storage Manager problem, thousands of posts easily turn up. Like this one on Intel's user forum, with 500+ replies. And there are multiple other threads like that, just on Intel's forum. That oughta tell you something... A lot of the complaints are with version 188.8.131.523, and some reported success with reverting back to 8.8. I had no such luck. All other versions fared just as badly. I also saw reports on 9.x with the same problem. I don't think there's anything wrong with my hardware: once I put the drives on the lowly Windows dynamic disk mirror, things have been just fine.
I've used consumer fake RAIDs from VIA and nVidia in the past and never had much of a problem. Neither was run in a typical environment (VIA for Win XP x64 and NVIDIA for Win 2003 Standard x64), but they were just humming along happily. The nVidia machine even ran VMWare Server with 4 VMs. But the Intel stuff doesn't even work under a lightly used Windows 7 machine.
I couldn't believe Intel had unleashed such buggy stuff on users. Bad vibe for the overall reputable company. They need to get their acts together. If not, I guess there're plenty of chipset vendors to choose from. They may be the king of CPUs, but outside of that, make the steps carefully please!