New build instability issues

[maomatt]

I completed a first build a few weeks ago and had no problems initially, once I got XP Pro installed.

specs
Antec TRUEPOWERII TPII-550 ATX12V 550W Power Supply
BIOSTAR TForce4SLI Socket 939 NVIDIA nForce4 SLI ATX AMD
AMD Athlon 64 X2 4400+ Toledo Dual Core Processor Model ADA4400CDBOX
2 X Western Digital 320GB 7200 RPM SATA 3.0Gb/s
Western Digital 80GB 7200 RPM IDE (drive from old machine)
NEC Black IDE/ATAPI 16X DVD±R DVD Burner Model ND-3550A - OEM
SONY 1.44MB 3.5" OEM
2 X XFX GeForce 7900 GT / 256MB in SLI
2 Gig Memory Kingston ValueRAM 1GB 184-Pin DDR SDRAM DDR 400 (PC 3200)
Antec Performance I P180 case
this is intended to be a gaming/number crunching rig for work and play.

The machine ran fine at first, but after a short time began to behave erratically; locking up on XP longin or after being idle for a while. Thinking that I might be drawing to much power, I disconnected the non-boot drive and the system ran fine; so i added one drive back. It then locked up after being idle. SO I swapped in the other drive. And it locked up again. So I ran it with jus the boot drive. And it locked up.
After lockups strange things occur:
* I attempts to boot to an old Windows 2000 partition on the 80 GB drive, despite that drive being last in the boot order in bios
* Freezes at the DMI Verification screen. Rebooting again or unplugging power to one of the auxilarry drives usually corrects this problem
* NON SYSTEM DISK error until I insert my XP Pro disk, run repair, and tell it which drive is the boot drive
* ad nauseum

I am pretty sure that my HDDs are ok and the PSS is fine. I was hoping that someone had seen something similar before and could give me some hint or clue. I am hoping to avoid re-installing XP or RMA'ing components, but I'll do what I have to do...

thanks
maomatt

[glc]

Test your ram with memtest86+. Test your hard drives with WD Diags. Check your processor, system, and video card temperatures. Remove the 2nd video card as a test.

[maomatt]

The temperatures all check out fine and I've already tried removing one video card, with the same errors occuring. I'll test the RAM and HDDs tonight.

[MakeYourslf2012]

The PSU might not be suppling enough power. nVidia just added a seperate (more powerful) section of PSUs certified for double 7800GTX 512MB, 7900GTs, and 7900GTXs.

[glc]

Removing one card will take care of the power supply theory, and that's been done. The extra cert only applies to dual 7900GTX and 512mb 7800GTX rigs.

[MakeYourslf2012]

My mistake, sorry about that.

[maomatt]

All HDD's checked fine on WD Diag quick test. The machine always crashed before completing any extended tests. Will download DOS version and run it with memtest86 this eve.

Of note, perhaps? The rig seldom crashes while being used, except at initial XP login. If it gets past that, it is stable until left idle, even while playing graphics intensive games.

[maomatt]

The HDDs all passed the extended tests. The memory passed Memtest+ with no errors as well. The computer did, however, lock up once during memtest. Only one HDD was powered up during Memtest.
Also, I ran 3DMark06 the other day, just to get a feel for how fast the graphics were. Nothing spectacular, but I DID notice that only ONE logical CPU showed up in the system info. I compared this to other AMD dual core machine and they all had two logical CPUs. Is it possible I have a bad CPU?

Any suggestions?

[maomatt]

Part 2 of the repair...

http://forums.amd.com/lofiversion/index.php/t58229.html

Apparently I selected the wrong ACPI option while installing windows. Hopefully this will help the instability inssues, as well