SilverStone Strider ST56F 560W - crapping out

I just got a shiny brand new 560 Ti to play with yesterday, and after hooking it up to the PC every benchmark I ran caused a shutdown, even games. Is my power supply most likely the culprit?

My previous setup before the new card:

SilverStone Strider ST56F 560W
550 BE X2 to X3 @ 3.75GHz
Asus 4830 @ stock
500GB WD Green
250GB Barracuda
80GB Barracuda
SB Audigy
8 fans in total, mostly 80mm
DVD-ROM, but that likely won't matter

I know the ST56F has separate +12v rails at 18A each, but usually the CPU and/or the PCIE 6pins get their own rail. The ST56F comes with two of these 6pin connectors, which once I start any intensive benching or gaming the PC shuts off.

I tried plugging a molex to 6pin to try the other rail, but the PC cuts to a stop a split second after hitting the power on.

Any thoughts?

The 560Ti uses about 11-12A on full load, leaving 6A for the rest of your components on the same rail. It is possible that it is not enough power for your 3 HDD's, fans, and other components that require it. Try disconnecting a few HDD's if you do not need them and try the video card testing again.

Just tried setting my processor OC to defaults and the card runs wonderfully. At this point I'm pretty sure that it's the PSU that's choking up.

I just had a psu start dieing on me. I would leave the cpu at stock and over clock the GPU. If it shuts down I think its the PSU.

Let us know.