It looks like overtime my fps on H2V has been gradualy degraging or somethin :/

For example the last games I have played my fps as dropped as low as 30 fps for the whole game.. but if i go into a closed off area or somethin it goes back up to 150

specs: e6600, 8800 gts oc2, 2gb ddr2

I run the vista performance score again and all the scores come back exactly the same :/ anybody have a clue whats goin on