4670K overclocking issues?

[MaTpr0F]

Hi everyone!

I recently upgraded my system here's my specs:

i5 4670K
Gigabyte Z87P-D3
Gigabyte GTX780 OC
Kingmax ddr3 1333 3*2GB + 1*4gb
Seasonic G650

Fresh install of Win 8.1.

So the problem is I tried to OC my cpu. I set the multiplier to 4.2 with 1,27 vcore voltage. Everything else is on factory settings (uncore, vring, etc)
Prime95 runs just fine for an hour, but I get random crashes in Black Flag (one time the sound&screen freezed and needed to reset) and in BF4 (maybe it's irrelevant because it's chrasing anyway). Checked cpu temps, everything is normal 55C max while gaming.

What could be the problem? Unstable OC? I think this voltage for this clock should be enough and also don't think that I reached the OC limit of this cpu.
Or mabye the memory is slow?

Many thanks for any kind of help!

 

[Davil]

There are a lot of possibilities here. Are you sure that your vcore is in manual and not adaptive or offset? Also your memory settings can effect things. An hour of prime95 is also not really the best test of stability, you'd need to run it for at least like 4 to be fully confident. Check your crash dumps with something like BlueScreenView to make sure it's a hardware related error and not like a video card related error. You can try with less RAM and see what happens. You can change the your memory to the XMP profile which might help. You should also try a lower setting and see if those are stable in game.

In my experience if it's having problems during games it's probably heat related in some way or another. Just because your core temps are good, doesn't necessarily mean the rest of your system is adequately cooled.