10-50% CPU used by xorg?

[Simon Thum]

> Ahhhh ... the 'window-wanking' test. If you must do this as part of
> everyday use, then run a compositing manager. If you don't want any
> compiz special effects, then the best performance is with XAA,
> XAANoOffscreenPixmaps set, and xcompmgr.

Since you seem to have played a bit with that, I've got a stupid 
question bugging me:
For my system (currently ati with XAANoOffScreen), the XAANoOffScreen 
lets me toggle good console perf vs. good firefox/thunderbird perf, with 
the other one darn slow. Isn't there someting like 
XAASensibleOffscreenPixmaps that avoids the bad cases? (or is it hackable?)

Thanks in advance,

Simon