Need help!!

This is my rig:

AMD 64 3800
MSI RX800 TD 256 version
1.5k ram (512X3 333mhz)
nForce4 ECS 40 A939 mobo

I Just upgraded to this system, and everytime I try to run a game, (CS:Source and, UT2004 mostly, both games on 1024 resolution, and Normal settings) I notice that whenever I turn corners my FPS will drop, or it will become incredible choppy (70fps to 30-40fps). I have tried installing several different version of Catalyst drivers (6.9, 6.7, 5.12, 5.7) and I still get the same result. Also re-installed windows a couple of times, and I think i have come to a conclusion, that the problem is one of my hardware. Anyone have an Idea, what could possibly be causing this?.

I Also tested my ram, and they seemed fine, even left one at a time, and I was still getting the same result.

Thanks in advance.

 

I think I posted my question in the wrong forums. I got a feeling that I Should've posted in the game forums... Couldn't find the delete/edit option, so Sorry if I did post it in the wrong forums. Gonna Repost this in the game forums. Thx