https://bugs.freedesktop.org/show_bug.cgi?id=39714
--- Comment #13 from Michel Dänzer michel@daenzer.net 2011-09-07 03:29:22 PDT --- The MTRR/PAT info is the same before and after, but almost 60M worth of BOs moved from VRAM to GTT. So the first theory seems more likely.
That said, I'm not sure which buffer(s) could make such a difference for glxgears...