I did a clean install of the drivers and the problems seems to have gone away. Normal FPS drops rather than a near halt now. I suppose that problems may have arisen that I did not clean the drivers from my old nvidia card and some setting left over was causing some issue
Cheers for the HD tune tip, behaves normally but good to know if something comes up!
Re sli, you probably want it off for this game so that you can run physx on a dedicated card.
and regarding dead space he still runs so slowly! still i should probably give it another try before i dismiss it . I've been amassing cheap steam games of late (which Dead space is one of) so might take a while to get there again!