*The performance CPU governor lets your CPU frequency always to the highest available.

*The powersave governor sets the frequency to the lowest available.

*The userspace governor allows you to set the frequency manually, unlike the others.

*The ondemand and conservative are governors based on in kernel implementations of CPU scaling algorithms: they scale the CPU frequencies according to the needs (like does the userspace frequency scaling daemons, but in kernel). They differs in the way they scale up and down. The ondemand governor switches to the highest frequency immediately when there is load, while the conservative governor increases frequency step by step. Likewise they behave the other way round for stepping down frequency when the CPU is idle. The conservative governor is good for battery powered environments on AMD64 (but may not work on older ThinkPads like the T21). Ondemand may not work on older laptops without Enhanced SpeedStep due to latency reasons. Anyway, for recent enough Intel CPU, ondemand is the one recommended for power efficiency (over userspace, and even over "powersave") by the Intel's kernel developer Modules acpi-cpufreq cpufreq_ondemand cpufreq_userspace cpufreq_conservative cpufreq_powersave

# modprobe cpufreq_performance cpufreq_ondemand cpufreq_conservative cpufreq_powersave cpufreq_userspace

There are plenty of userspace frequency scaling daemons available: * cpudynd * cpufreqd * cpufrequtils * powernowd * powersaved * speedfreqd * laptop-mode-tools can also be configured to switch governors when the laptop is plugged in and unplugged

*Please Post a Comment with your cpufreq-info command out, thanks