[johnchristopher]

> Source: apple forums and http://mbp2011.com

Wow: “The problem might be on the GPU” Said the “Genius”. That’s exactly what I was hoping to hear (he didn’t mentioned this until I pushed them this far.) So I replied, “You all knew exactly what’s going on here and you intentionally kept this from the customers, right?” Right this moment, the “Genius” has left.

That's insane.

[mgkimsal]

They wouldn't run any advanced diagnostics on mine because I had 'too much ram' in it - model was rated for 8gb but I had 16gb. Not necessarily unreasonable, but... it worked fine for 2 years with that ram in it, and the problem was obviously video related. well, nothing's that obvious, but... they didn't offer to just unscrew the back, remove the extra ram, and run more tests - they seemed to want to not handle my issue at the store. "5 business days" without my business computer is a bit too much, and now I realize I need a fallback strategy. :/

[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.