Vista capped FPS?

Well I doubt it capped it but recently I formated my HD, installed a 8800GT OC from a 7800GTX OC
I went from XPSP2 to VistaSP1

All non-needed services and programs are off, usually run at about 600MB used RAM @ startup

Before the upgrade on my 7800GTX I could get COD4 and TF2 to and over 100 FPS (on low and med
settings respectively)

Now even at a low resolution with everything off on TF2 and seemingly ever other game I can GET up
to like 60FPS but am usually around the 30FPS zone.. no matter what.. was fine before upgrade

Benchmarks good, temps good everything SEEMS fine

Athlon X2 x64 2.0GHz
Vista x86 SP1
2GB DDR2 400 (PC3200)
3GB Pagefile (non-sys partition)
Defraged with PerfectDisk
200GB SATA
8800GT 512MB factory overclock
Latest drivers (set to app controlled)

The only things I know for sure is I wanna upgrade my RAM, and the MoBo is PCIe 1.0, card is 2.0

Any thoughts on what to try?