[slantyyz]

There's a lot of variability these stories in terms of how you're treated by a Genius when you take your computer in. When I took my problematic 2011 MBP in, they pretty quickly determined that it was a motherboard issue and replaced it.

Two months after my motherboard was replaced the video glitches started appearing again.

Coincidentally (or not?) it happens that I use Coda every day, and Coda forced Macs (inadvertently, apparently -- Panic used Apple's guidelines on how to implement this "gracefully", but Apple's flag was buggy) to use the discrete card all the time.

Interestingly enough, once Panic disabled the 'use discrete gpu' flag in Coda, my screen glitch problems basically went away on my new motherboard.

[kevinchen]

Graphics switching on dual-GPU Macs used to require you to log out when you changed the GPU. They never quite got the automatic switching right but it's much better on the current generation. I very rarely see random red-and-white checkerboard patterns flash on the screen.