Asus P5B Deluxe, Win XP RAID 0 , 1 Spontaneous Reboots

I just put together a new system with

Intel Core 2 Duo
Asus P5B Deluxe
4 SATA drives
Ultra X2 550 Watt power supply

I set up 2 SATA drives in a RAID 1 using the on board Intel controller, and then I set up 2 partitions on the remaining 2 SATA drives, one RAID 1, and one RAID 0.

I installed Win XP onto the RAID 0 partition for preformance. I have noticed nothing great from that decision, by the way, although I had to buy a floppy drive off ebay to accomplish it with F6.

However, after running without problems for a few weeks, I am now getting spontaneous reboots. I can't see them being related to anything, sometimes I use the computer for hours with no problems, other times it will reboot again and again and again.

Usually, after these reboots, or pretty regularly when I turn the system on now, the RAID 1 partition (across the drives with the RAID 0 O/S installation) is degraded and being rebuilt. I see that from my Intel Storage Manager software in my startup tray sending a notice.

This indicates to me that the RAID setup is going haywire and causing these reboots, but I can't be sure.

I have tried going into My Computer -> Properties -> Startup and Recovery and unchecking the 'reboot' option, but this did not help.

The system is full of fans, there's a CPU fan, and large diameter fans in the front and back of the case.

Any ideas?