CacoFFF is right, it might be a drivers issue. W7 automatically installs drivers for the GPUs, but this drivers cause me some trouble, and low perfomance ( I own a 9800 GTX)
U should go to nvidia site and download the newest version of video drivers... I think the WHQL is now 186.16, at least when I updated my drivers was that
U should go to nvidia site and download the newest version of video drivers... I think the WHQL is now 186.16, at least when I updated my drivers was that

