Soldato
The 352 drivers have been really problematic for me and my 980 GTX, using Windows 8.1 x64. Either black screens with an odd flashing cursor or driver failing to respond and then recovering.
Gone back to the 350.12's and, thankfully, all is well after using a driver cleaner.
Gotta love PC's.
I'm running 8.1 as well with a 670 and haven't had any issues with 352.86, yet the 350.12 driver caused flashing textures, and "display driver stopped responding" errors.