I also read that having X11 running apparently switches to the discrete GPU. Now, I have no idea why it would do that (GLX extension?) but that kind of sucks given that I spend essentially 100% of my time in an xterm. (If anything, X11 graphics is so slow anyway that I don't see the point of ever switching to the discrete GPU for its sake.)
Really, Apple needs to fix this. If the application requires < x resources, or if the frame drawing time is < y, then stick with integrated graphics regardless of API used.
Really, Apple needs to fix this. If the application requires < x resources, or if the frame drawing time is < y, then stick with integrated graphics regardless of API used.