tips for bugfixing this situation.
1) get latest GPU drivers from NVidea
2) Uninstall previous drivers, reset pc, run ccleaner's regestry cleaner AND the general trash removal
3) install new NVidea video card drivers, follow instructions.
check FPS if no improvement follow the next instructions
4) go to ASROCK's webpage. Download latest BIOS and MB Drivers for your current MB
5) install latest MB drivers.
check FPS, if still no good go to #6
6) install latest bios
check FPS, if still no good
7) clean install windows, something is broken somewhere and it isn't the drivers. Save the new drivers for the MB and GPU before formatting your drive.
Generally speaking I've never seen this problem last past this step. If its still there i don't know what to tell you except your video card might be broken in some way...