[flomo]

Have the same model with the NV graphics, and have had occasional video glitching since I bought it refurbished. Crashes were rare until Yosemite, and perhaps my DP port is getting funky. I've wondered if these are also semi-defective, but it hasn't been well publicized. In any case I've gotten a ton of mileage out of it.

[72deluxe]

It would be interesting to see what Yosemite is doing with the GPU. If you could download and install Quartz Debug, you can get it to flash areas that are drawn with accelerated graphics in comparison to CPU drawn graphics. It would make an interesting comparison with Mavericks and previous.

Interestingly, the one change they did make in Xcode 6 was that the build progress bar at the top of the screen is now drawn in software - it used to be the only thing in the entire IDE that was GPU accelerated!