windows 7 - Image and sound freeze during gaming, after crash during nvidia gfx driver installation

I encountered crashes during gaming (like Doom etc.), meaning freezed image and sound. A bluescreen wasn't even shown and I had to turn off power.
These crashes occured during workload, but no overheating nor real heavy workload (no oc).

I reinstalled the os, first gfx driver installation went without a problem and I had no crash for enough time to say it was fixed. After some time I updated the gfx driver and during installation my pc crashed (this has happened before the time of reinstallation too and may be the original cause).
After this one crash I encountered again multiple crashes during gaming.
Interesting thing: I installed a diagnostic program that is saying what caused the crashes. It said that the first crash was cause by the nvidia driver, but the crashes after that by windows os.

The mainboad was checked and is not damaged. My hardware is:
GPU: Asus GTX 970 Strix OC
CPU: Intel i7 4790k 4GHz
Mainboard: Gigabyte Z97P-D3
Memory: G.Skill DDR3 2x8GB (F3-2133C10D-16GXM)
OS: Windows 7 64bit on SSD

I dont know what driver version was responsible for the crashes, but I think that this is not important since that has happened at multiple different times (also my pc is currently split into multiple pieces).

PS: I did not find the exact memory identification (F3-2133C10D-16GXM) in the mainboards compatibility list. Is that really important or just a recommendation since DDR3 and the mhz are already supported?

EDIT: No black screen, just a freezed image. For whatever this detail is key.

EDIT: Memory tested and no error found.