graphic issue ingame, driver problem, OC or game engine issue?

i want to get out of this doubt, i have this graphic glitch in unity

OCed both gpu and cpu



Stock both cpu and gpu



i don't think that's part of the pre-built glitched abstergo level since i didn't saw this before in my gtx 660 and this the only game i see that kind of artifacts and glitches.

any toughts?

graphic issue ingame, driver problem, OC or game engine issue?