Problems with 7900 gt

[Lateralus68]

I got an XFX 7900 gt EE 2 days ago and had read about the problems some people were having with them before this. I played FEAR for a long period after installing it without any problems. Day 2 of having the card though I have started to have issues.
I got some awful artefacting while playing Tiger Woods 2005. Decided to run 3d mark 06 and had no problems until the deep freeze bit when the artefacting happenned again although the test did finish ok. Score 4239.
Did the test again with artefacting during deep freeze but not locking up or crashing.
Should I be looking for another card??

 

[Lateralus68]

Tried 3d mark again...it starts artefacting at 52 seconds and then struggles to reach the end of the test. I am a bit of a novice when it comes to returning pc stuff...so what should i do now?
Of course sending it back will mean i am without a pc while waiting for a replacement not sure i can cope!