glxgears doesn't consume CPU

[Paco Ros]

Hello.

I've found a very strange thing in my Hoary.
Hoary is installed in a Comapaq laptop powered by a Athlon XP Mobile and
a Ati Radeon IGP (a.k.a. Mobility U1).

Hoary's X.org version enables 3D acceleration thanks to DRI and DRM
module.

Hoary kernel is stock kernel (properly updated) and powernowd is also
installed out of the box.

My CPU marks 530 MHz when I do nothing with the laptop, but if I execute
glxgears, it runs reasonably well, but CPU usage is over 10%

You can see this screenshot with cpufreq applet up right on the screen,
top and glxgears executing here:
http://bergantells.net/~paco/tmp/glx-gears.png

I the gears window is moved, then the CPU usage increases, powernowd
increases CPU frequency and more FPS are gotten!

The question is: Is a normal thing a intensive OpenGL application using
only 10% CPU?

I've got Debian Sid installed in a P4 HT cpu with a NVidia GeForceFX
card and CPU gues immediately to 100% when I run glxgears.

If this is a bug, I don't know where id the bug:
- powernowd is working fine becausa CPU usage is only 10%
- Radeon drivers are working fine
- OpenGL libs maybe?

Sorry, I have no idea about the problem origin :-)

Kind regards.
-- 
Paco Ros