Originally Posted by Stephen Warren
If you have physically separate X screens without Xinerama, they're named ":0.0", ":0.1", and ":0.2". Perhaps try experimenting with those DISPLAY values? But, if it's displaying on the screen physically connected to the faster GPU, it's extremely likely it's rendering there. Xinerama might complicate things; I forget exactly how that works in OpenGL.
Thanks for the reply,
So with Xinerama running, I have the game extended halfway on to the left and right monitors. So instead of having the full 4240x990 resolution I have it at 3000x990. You don't think it's not using the faster video card then?