HUGE drop in performance

[MightyMouse]

Hey guys how are you all doing?
I am big into playing online games and lately I have been playing ALOT of Day of Defeat, great game. I play on frenchy's pit, they have about 4 servers that all run DOD. When I first started playing there everything ran great, no slow downs, no lag, nothing. Then all of a sudden one day my performance just went down the tubes for no apparent reason. I had changed nothing, not installed any new hardware, nothing. After some frustration I decided to reformat, which I just did, and also because I bought a new video card. After reinstalling everything, I am still experiencing a huge decrease in performance and I can;t figure out why. I checked my bandwidth with a test, and it runs great, can;t be my video card its brand new, and I am assuming it can't be any weird programs running in the back ground since I just reformatted. This is extremely annoying, what could cause such a sudden drop in performance? Are there any tests or changes I can do to try and correct the problem?

Oh and just to give you an idea of how bad it is. I used to get 100fps steady with 1-3 choke and loss. Now I spike between 50 and 100 fps and my choke has gone up to probably an average of 50 or more, sometimes staying steady at 100.

Any help would be greatly appreciated!!

specs:
WinXP Pro service pack 2
Ati Radeon All In Wonder 9800 Pro 128MB