You'd better hold off until nvidia releases a new driver. Build 16299.15 (rs3). EDIT: - Cleaned with DDU. Installed driver again. No luck. - Repeated operation: DDU. In the middle Windows updated to 16299.19. Installed driver. Performance is back to normal. Weird EDIT2: The issue now comes on and off. When the problem arises the gpu clocks at a max. of 1987Mhz in Time Spy while it clocks at 2076Mhz when it works fine. It seems that reapplying the OC profile in MSI Afterburner fixes the issue temporarily. (Driver ver. 388.00) EDIT3: Ok, it was all cause by NZXT CAM software wich was messing with GPU.