strange FPS for CFS2

I have all 3 CFS's loaded, and love CFS2 but it has given me more trouble than even 3 has.
My game starts out with great fps( 200+) , online... then dips to unplayable levels ( 6 ). Offline, it runs fine, dips & peaks alot, but never under 120.
I recently reformatted to try to resolve it, but it still does it , but only online. I am on cable, and have all the best tweaks installed. My CFS3 gives me 40-60+ fps , for great play and doesnt matter if I play for 3 hours, but -2 drops off inside 15 minutes ?? then launch a new game and the same starts again in the same timeframe.
Any Ideas
I run W XP pro . I have tried to run it in compatitability mode, and every variant I can think of.
My game starts out with great fps( 200+) , online... then dips to unplayable levels ( 6 ). Offline, it runs fine, dips & peaks alot, but never under 120.
I recently reformatted to try to resolve it, but it still does it , but only online. I am on cable, and have all the best tweaks installed. My CFS3 gives me 40-60+ fps , for great play and doesnt matter if I play for 3 hours, but -2 drops off inside 15 minutes ?? then launch a new game and the same starts again in the same timeframe.
Any Ideas
