I'm struggling to get a p690 LP Plus PCIe x16 to work on a CentOS machine. I successfully compiled and installed the official drivers (1.4.6.2), configured xorg.conf, and now have a single screen for four monitors. However, the system is unusable, because any 2D translation (moving a window, click and dragging text, etc.) pegs the CPU, sometimes up to 100%. It seems that the GPU isn't handling any of the heavy lifting. Using tuxx-home's drivers doesn't fix the problem. I haven't seen anybody else with this issue.
I tried turning on busmastering in the Device section of the xorg.conf, but that didn't do anything. (Nor should it, as I understand it, since PCIe cards shouldn't have to enable busmastering, and even PCI cards should have it enabled by default.) Loading GLX fails with the xorg log warning:
(WW) MTX(0): OpenGL is disabled as this feature is not supported on this hardware
This strikes me as strange, since plenty of people seem to have OpenGL with their Matrox cards. But in any case, I think that OpenGL is only for 3D acceleration, so even if it were enabled, it probably wouldn't solve my problem.
I'm hoping that the fix is some silly xorg.conf option that I'm unaware of, or maybe an option that I should have specified when compiling the driver. Or perhaps an option I should have specified when compiling my kernel. I've attached my xorg.conf file, if that helps.
Thanks very much for any help/advice you can give.