Download GPU Z and look at the temperature during the game. I think it's 99% due to the fact that you overclocked it. reset memory and cpu settings

It hasn't happened in a few months - I think it was related to overheating - both times it happened it was summer/hot and I was over-clocking GPU slightly with GPU TWEAK. Since I stopped doing that it hasn't occurred to this to this level. But every once in awhile I get little artifacts but no more full blown light show. Drivers are up to date and I have reinstalled Windows etc since this happened.

try to reinstall video driver

this is also possible due to a certain combination of settings within the game itself

Is your graphics card OK? Have you checked the integrity of the game files?

My guess is maybe it has something to do with your brightness setting but thats wild bro

Got the Rubik's cube texture pack installed lol