EX58 UD5 Sli Rebooting with certain games

[jamrowls]

Hello Everyone, I have a major problem.

Gigabyte EX58-UD5
Be Quiet Dark Power Pro 1200w
BFG GTX280 OC x2

1 card, either card, no problems.

2 cards FarCry2, Crysis Warhead, rFactor, Furmark, Vantage - no problems

2 cards GTR Evolution - reboots computer >1sec into intro

2 cards GTA4 - reboots computer >1sec into first load screen after starting a benchmark
50% of the time the actual game will play, 50% it will reboot >1 sec into first loading screen.

Instinct says PSU but I can load the comp to over 850w with prime and furmark, yet I try to load GTR at something like 300w and it reboots. Not getting anywhere near the game, litterally the first thing you see after starting.

I have searched and searched for motherboard problems, PSU problems, GPU problems, Game problems and cant find anything.

[Doomas]

Not all games works with Nvdia , and even less with slim...