Video Ram Tester?

Hey guys.

I recently bought a new card, the:
eVGA GeForce 7950GT 512-P2-N637-AR KO Superclocked Video Card - Retail
GeForce 7950GT
512MB GDDR3
PCI Express x16

And it plays very well at high res...

Except, after a while of playing Dark Messiah, I get some strange artifacts. Things like fluorescent graffiti on shaded areas, or faces of walls. Once or twice, I get a sort of pinpoint flat-surface radial thing where all I see are a bunch of triangles converging on a few points on the screen (all basic shades, no textures). Similar to the effect you get when you fall through a "hole" in the map.

If I change resolution (does not matter which) it seems to reset this and work fine, but will return if I play a while. It will go away if I go back to the previous resolution.

I am wondering if this is:

a) A video RAM issue.
b) a system RAM issue.
c) A driver issue
d) An issue with the game program

I am wondering how I could test this.

One way is to, obviously, play another game for a few hours and see if it will happen there. I think Company of Heroes is taxing enough that it would show any problems with the video/computer hardware or drivers.

But if the error appears there, the only thing that would eliminate would be a glitch in DM.

Any clues on what might be causing this and what could be done to solve it?

TIA!

Pardon all the typos on the first post there (Vedeo??!?)...

Anyway... I am not sure it is an overheat problem... The case I have is a LanLi Silver 60A with a 120 MM side fan mounted almost directly over the card... It has a small top fan, and a larger front and rear fan as well...

Does anyone have any 3rd party software that could enable monitoring while playing the game? (I have the Logitech gaming KB with the LCD screen, it would help if I could see more than just CPU and Memory on the output...).

Could CPU OC'ing also produce graphic artifacts? I have it cranked up a bit, but well below what has been achieved stock for the E6600, and I get no hangups or BSOD's while playing....

Anyway, thanks for the response!!! Looking for any thing else that might be the problem... Hopefully it is nothing serious....