My graphic card keeps crashing and recovering randomly when playing games such as assassin’s creed black flag and battlefield 4.

I’ve tried reformatting my computer but issue still persist.

Please advise.

Windows 8 Pro 64-bit
Z97MX-Gaming 5

Intel(R) Core(TM) i5-4690 CPU @ 3.50GHz (4 CPUs), ~3.5GHz
2x 4GB RAM

NVIDIA GeForce GTX 960 (GV-N960WF2OC-2GD)