Thank you so much, guys. I'll have to wait to get home to try it but this sounds right on target. Here's what I got.
MIT-SHM version 1.1 opcode: 148, base event: 99, base error: 172
shared pixmaps: no
I never experienced any 2D slowness, ever. Maybe the fact that I only use fvwm2, xterm and occasionally emacs has to do with that?
Seriously, where could I notice slowness?