Problem with my Rig.

Hi,

I have a major problem with my gaming rig. And i can not seem to identify sure problem or how to fix this.

My PC like to turn off then restart when I play Battlefield 3.
I have updated all of the drives and Hardware on my PC.
I have run Ram Check, no problem there.
I have run FurMark and Heaven Gate GPU stress, and it does not shut off.

I think its my CPU over heating? That's the only thing i can think off. If anyone have any suggestion or comment please help.
I play BF3 on 1920x1080 Res

Here is my build
Case: HAF X
PSU: OCZ ZX Series 1000W
CPU: Intel Core i5-2500k
Mem: G.Skill Ripjaw X Series 8GB DDR3 1600
GPU: EVGA GeForce GTX 560ti x2
Mobo: Asus P8Z68-V Pro
SSD: OCZ Vertex 3 Series 120GB
HDD: WDC Black 1TB

Cooling on top of what come with the case.
CPU Fan: Noctua NH D-14
Scythe Ulta Kaze 120 x 38mm Case Fan (45.90dBa, 133.6CF) x2
One for GPU cooler and one for top of cause exhaust.

Please let me know if you have any input or comment or suggestion. I will be much appriciated.

Thank you.

follow my fah guide here install and run both smp and gpu clients and tell me if you get any errors in in the clients or if the pc shuts down.