With Gnome System Monitor 2.22 under Debian testing (Lenny) I had the problem when I clicked on the Resources tab the CPU usage would got to 100% on my laptop and desktop.
Well I have been able to fix the problem on my laptop which has and Intel video card by adding Option “AccelMethod” “EXA” to the Device section in my xorg.conf file.
Section "Device" Identifier "Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller" Driver "intel" BusID "PCI:0:2:0" Option "AccelMethod" "EXA" EndSection
When I have worked out how to fix the problem on my desktop using a Nvidia video card I will post the solution.
Thanks goes out to MistaED for pointing out to me that this a problem with the way Cairo rendering is done.