Is there anything missing from this diagnosis? (psu or card failure)

About a month ago I began my ordeal to upgrade my video card from my sturdy little 7600GT...

I have tested three cards and two power supplies, I'm getting texture failures that start out looking like this:

and then eventually the card just locks up the game (or, worse, my entire system).

First card bought, BFG gtx 260 running on a Raidmax 530 watt. This marks the first appearance of the failure.
Tried another card: EVGA gtx 260 (which was dead on arrival).
Tried a third: EVGA gtx 260 which showed the same problems as the BFG.
I read about how Raidmax power supplies suck so I replace it with a Corsair 650 watt (it's very pretty, <3 Corsair).

But now, even with a quality power supply, I'm still getting this horrible texture/lockup issue. Have I put in my due diligence? Is it officially the card's fault? Is it reasonable to expect 2-3 replacements before I find a card that works? This is my first major upgrade, I didn't know what to expect but it's becoming a nightmare...

Thanks for any insight.
-S

Try reinstalling the game. If it doesn't help, uninstall your current drivers and install the latest drivers from the nVidia website. It doesn't sound like it's the GPU's fault, especially since you tried different cards yet the same results occurred. Does this happen in any other game?

Have you monitored the GPU temps under load for a while?

OK I just finished a full cleaning and reinstallation of the current nvidia drivers, still no dice.

I even maxed out my fan to 100% but the temps never went above 45C anyway.

Bad card? I'm thinking bad card.

Is there aaaaanything else? Could my system RAM be interfering*? I just find it so hard to believe that I could get three dead cards... Should I bother getting one of those power supply checkers from newegg? This is turning into such a money pit



*(2x512s and a 1g, they have never given me problems before)