Bad GTX 570?

Hi,

I have just built a new PC, here are the specs:

CPU: I5 2500k
MB: Asrock Z68 Pro3 Gen3
PSU: OCZ 700W
GPU: GTX 570 (driver Nvidia 296.10)
Memmory: Gskil Trident 2Gb x 4
OS: Win7 ultimate 64bits

All components were bought new, except for one of memory modules, which was working fine in my older system.
I have fully updated Windows. I think I have installed pretty much all necessary drivers for the motherboard.
...and the system seemed stable and ready to go!...Until I ran my first game, the Nvidia driver crashed within 1 minute of executing (error code 7 - TDR timeout). Then I tested a few other games, and all seemed to hang up or crash as soon as you enter in some sort of 3d processing. I tested OpenGL and DirectX games and all were affected.
I thought it was the GPU, so I download Furmark and ran the burn in test expecting it to crash also. To my surprise it finishes a 15min test, with the load temperature located on the high 70s Celsius.
I have already physically reinstalled the card. I also did a clean installation of the Nvidia driver, but to no avail, the problem is always the same.
I have also removed and used the different memory sticks individually.

My next step will be installing my older GPU to try to exclude a motherboard/CPU/memmory problem.

But my main question for now is if it would be common to have a faulty GPU that makes the driver crash but stands an artifical stability test like Furmark?

I read somewhere Furmark doesn't test every part of the GPU, so maybe it makes some sense that a game will use much more diverse components in the graphic card and therefore may still crash due to bad hardware. Though I would like to know the comments of someone with more experience on this.
Or if since Furmark test is good, I should turn my attention to the motherboard instead.

Thanks in advance for any input into this question which is really irritating to me.