Originally posted by: SuperTyphoon
why trade a 6800nu for a 6600gt?
I agree. Unless your card is defective, a 6800nu will beat a 6600GT in almost every situation, and a 9800XT won't even come close...
If you are only getting 20 FPS in Counter Strike, then something is wrong with your system or your configuration. As others mentioned, memory is a good place to start.
Upgrade your memory if you don't have at least 1 GB (if possible), run a defrag on your hard drive, close ALL background applications, then try again. If you still get low frame rates, run some tests with 3DMark and see what kind of scores you get. If your scores are good there, something is wrong with your CS install/configuration. If your 3DMark scores are low, you'll need to do some additional troubleshooting on your machine as a whole (do CPU only tests such as SiSoft Sandra's CPU benchmark, run MEMTEST to check your memory, etc.) to find out the source of the problem.
Also, download and run DriverCleaner to completely remove all traces of your video card drivers then download and install a new copy of the drivers from Nvidia.
If all of this fails, then yes, I would look at replacing the video card. But if you can't confirm that the problem is actually with the card itself, then downgrading to a slower card isn't going to help...