I am at a loss. Here are a few more ideas to examine:
- Check which libGL you are actually using with ldd.
- Check for interrupt storms with vmstat -i
- Disable SBA (I doubt this would cause it
- Compile without VM86_INT10CALL. I am guessing that is why Xorg.log is loading the int10 module?
- Maybe TwinView is slowing you down? I do not have it enabled, so I do not know.