I'm not that fussed by lots of visuals to be honest. I play plenty of games on DX9 and they all look fine. Graphics don't make a great game, in my opinion. Just as long as it runs smoothly.
I didn't think the 7900GT even supports DX10?
The RAM works if I take out the 1GB stick, and also if I take out the 2GB stick and replace it with the other 1GB. It just doesn't work with all 3GB. The computer boots up, and it even recognizes all 3GB, but when it gets to loading up Windows, the screen just stays blank. It's really strange.