Fedora has build in support for speedstep technology. Very nice. The release notes state: It is also possible to set minimum, maximum, and policy using the following boot-time parameter: cpufreq=<min>:<max>:<policy> I modified my grub.conf as follows: title Fedora Core (2.4.22-1.2115.nptl) TEST root (hd0,2) kernel /vmlinuz-2.4.22-1.2115.nptl ro root=/dev/Volume00/Fedora hdc=ide-scsi cpufreq=600000:1200000:powersave rhgb initrd /initrd-2.4.22-1.2115.nptl.img After booting /proc/cpufreq is empty and lsmod doesn't show speedstep-centrino. Obviously the boot parameter does not load the necessary module. Do I miss something? Is it a bug and worth a bug report? The only way I found to make it work is to add the necessary commands to rc.local. Peter