Hi,
I run Slackware 12.1.0, with latest custom kernel and KDE .
My graphics card is an old ati mobile radeon (mobileFireGL 9000, 64MB).
512mb ram, 1.7GHz Centrino
I had this *random* problem when I started X (as a user running startx, the problem didnt appear running X as root)...
Everything halted exactly each 3-4 seconds (glxgears, keystrokes...).
I saw nothing weird when running top/htop, cpu looked OK. The notebook has 512mb, so that wasn't the problem eiter.
I had DRI and GLX in my xorg.conf with correct permissions for normal users and no errors whatsoever in my xorg.conf.
Long story short :
Recompiled my kernel took *ondemand* as a *default* cpu-governor instead of *userspace*.
PROBLEM SOLVED !
could be handy for others having this prob