CPU frequency scaling
1- use speedstep-centrino kernel module :
modprobe speedstep-centrino
2- use ondemand scaling governor :
echo ondemand > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor
3- or use conservative scaling governor (new in 2.6.12rc6 kernel) :
echo conservative > /sys/devices/system/cpu/cpu0/cpufreq/scaling_governor