Originally Posted by spion
this post is BULL****.
Does it affect some realworld applications too or is glxgears really the only 3d application you run?
Wait a second.
You'd better think (and maybe google) before you insult someone.
The glxgears performance drop may
be a problem if too big. See this
So the only thing glxgears really tests is the performance of glXSwapBuffers() - basically, how fast we can push render buffers into the card. This operation is slower with DRI2, but - roughly speaking - unless it was an order of magnitude slower (e.g. glxgears drops from 1000FPS to under 100FPS) it wouldn't make any real difference.
On the other hand, use some other benchmark like e.g. the unigine
Edit: but first try disabling the X86_PAT in the kernel (see nopat above).