I'm getting the symptoms of a graphic processor unit failure. Green and pink pixels have been dancing across my screen for awhile now. If I close my mac when its still on and re open it, the pixels are everywhere and its frozen. I have to do a hard reboot to regain access. I've been able to use it as normal, the pixels aren't always present but i'm guessing this problem is only going to get worse. Has anyone else had problems with this model? I'm wondering what the best option is. This seems like its going to be a costly repair. I would appreciate any and all advice. Thank you so much.