Crossfire Killing my Computer?!?!

My apologies for the long post, but I'm starting to tear my hair out on this one...

My setup:


OCZ Gold 6GB (3 x 2GB) 240-Pin DDR3 SDRAM DDR3 1600 (PC3 12800) 8-8-8-24
ASRock X58 Extreme LGA 1366 Intel X58 ATX Intel Motherboard
Intel Core i7-920 @ stock
SAPPHIRE 100281SR Radeon HD 5870
hec Zephyr 1000 1000W ATX12V V2.2 / EPS12V V2.91 SLI Certified CrossFire Certified 80 PLUS BRONZE Certified Modular Active

All of this is brand new. I put everything together, installed a fresh copy of Vista, and everything SEEMS to be working ok, until I start to game (minus a little initial headache, see below). So far I've tried COD4, Trine, and X3, and for all three the system hangs either during an intro movie or as soon as the game proper loads. A couple of times COD4 just crashed to the desktop, but more often than not the whole system freezes requiring a restart.

So I pulled one of the cards out of the case and ran everything that way. No problems. Everything works great. I switched the cards to see if maybe one of them was defective; no such luck; when running on its own, either card runs fine. Put both in together, though, and it freezes.

So I thought it maybe was a power supply issue. I switched out the one in my current setup with an older (as in two years old) 600w supply, which supposedly is enough to power a 5870 crossfire setup (from what I've read online). EXACT same results as before. One card, great. Two cards, system freeze. I switched hard drives. Same result. Popped in my old 8800GTX. No problems. Plugged the computer into a different outlet- same problems. This leaves me with three possibilities: either the ram is bad, the motherboard is fubar, or both of my power supplies are screwy/inadequate.

I'm leaning toward the motherboard, cause when I first put everything together, the whole system was massively unstable. I ran memtest which returned a few thousand errors in about a minute. Turns out that the mobo had automatically set the timings on my ram to 7-7-7-58, which screwed the whole system up. Manually setting it to 8-8-8-24 fixed most everything. Except this game crashing issue. I would think that if it's a ram issue I'd still see instability issues (and continued error reporting in memtest, which ceased after manually changing the timings)

Anyone else have a crossfire setup with this mobo? Is there a setting I'm missing in the BIOS? Any thoughts/ theories would be greatly appreciated..

Try slowing your RAM to 1066 without changing anything else and see if the problem goes away. If it does, figure out how to get your RAM stable after you've confirmed.

i have not heard of that power supply brand. maybe a shitty power supply.

Well, if it passed 80+ certification, it can take full load without blowing up. Considering that it's a 1000W unit, that almost guarantees that power isn't the issue.

Thanks to all for the advice. I had to run out of town on an emergency trip, but as soon as i get back I'll try your suggestions. Couple of follow-up questions:

Siddsm- bumping up the vcore didn't seem to help. I also tried bumping up the pcie voltage a hair, just for giggles. Still no dice.

annisman- I'll run speedfan and post the temps, but i don't recall seeing a temp listing specifically for vid cards in there. I suppose they'll be among the oh so descriptive "temp 1", "temp 2" or "temp 3" readings. I do remember the cpu core temps hovering around the mid to upper 30s. The nebulous "temp 3" read something crazy like 129 degrees, which can't be right, since i think my motherboard would have melted at that temp.

Crashman- I'll try slowing the ram down, see if that helps. I still think it's kinda odd that the bios didn't accurately detect the timings of my ram, but once I manually fixed that, I ran memtest+ from a bootdisk for close to an hour with no errors reported. Could the ram still be the culprit if memtest checked out ok?

All: I'm also wondering if it's an amperage issue. the psu I'm using has 24 and 28 amps on the 12v rails, if I remember correctly. Somewhere I read that these cards want something around 55. Anyone know if that's true?

Again, thanks for the feedback.

MSI has a very good temp monitoring/ overclocking tool called MSI Afterburner, it is based on Rivatuner so it give lots of info on gpu load, temps, voltages etc. in real time. http://downloads.guru3d.com/MSI-Af [...] -2392.html