FWIW: I found this thread seeking others who've had problems with NVidia RAID 5. I installed a Win Server 2003 trial copy on a GeForce 6150 NForce 430 mobo about 5 months ago using 4 40GB Spinpoint SATA drives as bootable. Worked fine and was about to reinstall another OS when I thought, "Lets see if this fault tolerance really works."
It doesn't!
I unplugged a SATA data cable and BAM! the Blue Screen of Death! But that was the good part. I just shut down, replugged in the data cable and rebooted. Seemed to work okay; no errors reported. But I went into MediaShield and did a Synchronize (which took about 2 hours.)
Then I thought, "Okay, let's try pulling a power cable out of a drive." This time a message from the system tray popped up indicating a problem and MediaShield reported a Degraded condition and listed only 3 drives. That's more like it! But wait, at that point the system nearly froze. My mouse was active, but no hard disk activity took place at all for 5 minutes.
I rebooted, a red Degraded message came up and Win would not boot. (Funny how the GUI MediaShield doesn't seem to help when you can't boot your OS. Maybe using RAID for a boot drive is permitted, but not such a great idea?) Rebooted and used F10; seemed only option was to rebuild, but manual seems to indicate you need another spare disk for that.
So I shut down, replugged in cable and booted. No Win again. Rebooted and used F10 facility. This time I received two lines:
BOOT ID STATUS VENDOR ARRAY MODEL NAME
Yes 1 Degraded NVIDIA RAID5 111.81G
N/A 2 Error NVIDIA RAID5 111.81G
Tried to select Rebuild. Nothing happened. Machine is basically dead.
Is this a joke?

:!: The only postings I see about this are those asking if anyone is finding success with NVidia RAID. All the literature from NVidia talks about what a secure, fault tolerant system this is. Seems to me it flat out DOES NOT WORK. I'm glad this was just a test machine and not a critical file server.
Please, someone prove me wrong or direct me to a site that shows there's a way to make this work.