So, occasionally when I'm In city's I'll have weird... Glitches... Where parts of my screen will flick black or yellowish. Usually in weird shapes like unevenly long triangles. This happens when the graphics are turned Up or down. My computer is no pushover, I'm running a 3.0ghz amd processor with a radeon 7770 gc. 750 watt psu, and 4gig of ram. I got my pc about... Nov. Of 13, so not too long ago. But this just started maybe a mint ago doing this. I'm fairly computer savvy, but can't figure it out for the life of me. Any ideas on what's wrong or how to fix it?