What is your driver version, and have you tried a different driver?
How to determine your nVidia driver version
Right click in any open area of the Windows desktop
Select NVIDIA Control Panel from the popup window
Select SYSTEM INFORMATION at the lower left corner
Driver version should be the 1st line in Details
I have a GTX760 using driver 335.23 and Win8.1
•For Windows, do NOT rely on Windows Update to have current driver information
•-you need to go direct to the vendor web site and check updates for yourself
•nVidia Driver Downloads http://www.nvidia.com/Download/index.aspx?lang=en-us
Also NOTE that newer MAY not mean better, so be prepared to try an older driver
•-Old Drivers http://www.nvidia.com/Download/Find.aspx?lang=en-us