[Jefe]

So I've build myself a server with the following parts:

4U Rackmount case w/ 1x 120mm front fan and 2x 80mm rear fans
iStarUSA TC-500PD1 500W Server PSU
Asus M2N-LR motherboard
3 x Western Digital 160gb Sata 3.0 in RAID 5
AMD Opteron 1214 Santa Ana 2.2Ghz AM2
4x Kingston 1GB DDR2 SDRAM 667 ECC Unbuffered
Samsung DVD-RW SATA
Windows 2003 Enterprise x64 Ed.

The system went together fine, and seems to operate fine. All parts have checked out OK when tested using various methods. (Ultimate Boot CD, Burn-In software, etc)

Under a load the system has no issues and reponds quickly.

When left idle the system may stop reponding or reboot or power off. Since the day it was build on Feb. 7th, it has stopped reponding 3 times, rebooted 2 times and powered off 1 time.

I'm at a loss, I can't catch the machine actually locking up/rebooting/shutting down, I only find it after the fact. I've checked the event longs and nothing looks hinkey.

It only happens when idle. I've checked and re-checked that.

I only have one theory, and am testing that now. The motherboard can control the CPU fan speed, and seems to have it spin down quite low when the machine not under a load. I'm trying to see if it is possible that the CPU fan can idle so low that the motherboard thinks it's dead and tries to shut the system down. I'm turing off that feature so the CPU fan is full bore all the time.

Any other thoughts? I currently have it running another 5 hour test.