I am also experiencing this with latest Ubuntu 9.04 amd64.

My motherboard is P5W DH Deluxe, and I've tried various bios (enabling ACPI, EIST, CIE, etc...) and also factory defaults but the gnome applet frequency monitor will keep warning that the "frequency scaling is not supported for this processor".

I have a modern Intel Quad Core Q6700, which should support this feature.

Kernel in use is : 2.6.28-11-generic

The various modules discussed here are all missing from my configuration, even with cpufreq and powernowd installed.

Some outputs :
find: "/sys/devices/system/cpu/cpu*/cpufreq": Aucun fichier ou dossier de ce type
cat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor: Aucun fichier ou dossier de ce type
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_drivercat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_driver:
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors
cat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_governors: Aucun fichier ou dossier de ce type
cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
cat: /sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies: Aucun fichier ou dossier de ce type

Tt says (in french) that I have none of these files or folders on my machine.

Solution

reverting to an older bios, v. 2504, ASUS bios team : stop making cheezy bios, please.

http://dlsvr04.asus.com/pub/ASUS/mb/socket775/P5W%20DH%20Deluxe/P5WDH2504.zip

v.2503 Working Great? I'm not sure, I'll try to find out 2504.

v. 2602, v. 2704, v. 2801 did not support