I got the water cooled GTX 580 Hydro copper 2, 3 gigs of ram, awesome card! :)
 
It randomly restarts, especially when under load, but really at any random time it seems. :(
 
I can rarely get through a whole 3dmark vantage test which it scores P17364 FYI
 
The performance is awesome, Running arma 2 at really high caused the temp to get up to only 34C. I really like the card, just the random restarts impossible to live with, I noticed It happened in world of tanks (very low demand) until I set the xphysics to cpu. Now it doesn't really happen in WOT anymore and only in High demand games like Total war series and Arma 2.
 
I thought it was power, so I upgraded from my 800 wat to a 1300 cooler master PSU. Still restarting. :(
I tested the 8 gigs of ram for 10 hours with Prime95, flawless
 
Temps are all very cool CPU never more than 45c and GPU never more than 34c, but it restarts at any temperature.
 
Specs
 
Intel(R) Core(TM)2 Extreme CPU X9650 @ 3.00GHz
8 gigs of 800mhz ram
Asus P-5 ND board
I did not have this issue with my old GTX 280 water cooled card.
 
Im starting to think I just got a bad card, Any suggestions??
Thanks!!
-Gordak

Oh yeah, NOTHING is over clocked. Thanks

1300w is total overkill for a set-up like that. Sounds like a motherboard issue. Is your motherboard up to date with the latest BIOS?

OK, it lasts alot longer...  Just started crashing to restart again :(