Please list your system specs so to better assist you.

i7 950
P6X58D-E
Corsair AX1200
SLI EVGA GTX 570
Corsair H70
 
I think it's a bad card but I wanna make sure before I send it in
I jsut find it strange that instead of getting a BSOD or it freezing that it would just go black and reboot
 

I am leaning towards a CPU overclock or a MB issue.

kram36

big_willie are you using the 270.51 beta drivers? I was hammering on my system with some benchmarks a few days ago and I never got a BSOD when my system crashed, screen just went blank. I think it's this driver causing the no BSOD deal.

I've tried several different drivers including the 270/51 betas and I'm getting the same problem on all of them
Funny this wasn't happening about a week or 2 ago
Right now I'm using the latest WHQL drvers

hething

I had the same problem when my H70 sounded like this in my youtube vid. The computer auto shutdown when CPU temp is too high.. mine does it at 90deg C but it differs from Motherboard to motherboard.. This feature is there to protect the CPU from overheating and hence die..

It's not shutting down and my CPU temps are well under 70c when gaming
It'd definitely a GPU issue which I think I narrowed it down to either the drivers or the motherboard
I've played Crysis 2 for hours which both cards by them selves overclocked to 900/1800/2000 and they're both doing fine
It's once I enabled SLI that the problem starts

I get the same thing if I enable or disable sli in the control panel. Using 267 drivers

So I know software readings are the most reliable when it comes to voltage reading, but anyway I'm using HWMonitor to see what my 12v is at and it's showing it at 11.43 while folding with both cards at 900/1800/2000 with 1.050v.

rafale

I had the same problem with the 270 drivers when loading the combine test of 3Dmark11. It was very reproducible. What fixed it for me was to raise the ICH voltage from 1.125V to 1.15V and lowering my PCI-E clock from 106MHz to 104MHz. It was running fine before this driver set.

I jsut keep the ICH on auto because I don't understand it but I might give it a try

If I read correctly, you're using a AX1200 - so I doubt it's a power issue....
 
Black screen reboots sounds like a heat issue on the CPU / or cards (but you said it wasnt the cards)  SO reapply some TIM on your cpu. See if that clears it up.
 
 Next I would check for a short somewhere - which is a real pain to find ... either a grounding issue in your wiring to the wall plug or inside the case itself.
 
Good Luck.

So the fix was very simple
Like I thought the cards were pulling more power then they was getting
I finally received the Power Boost today and that solved my problem
Ran a few minutes of Crysis 2 with no crash and just finished a run of Vantage http://3dmark.com/3dmv/3061852