i tried around some more and it seems only msi afterburner causes this. this doesnt explain why my fps were so low with the gtx295 (maybe a sli problem as that one had 2 gpus?). I just started using msi afterburner a short while ago when i bought the gtx570 cause my old grafics card died.
but who cares about the old card, now it runs with very nice fps on the new card. thats all that counts 