Intel-undervolt: CPU undervolting and throttling configuration tool for Linux

Why would I want this? With a properly configured kernel, Intel chips can downclock to somewhere in the 400-800mhz range when idle.

Undervolting can make your CPU use less power and produce less heat. It’s popular for people attempting to overclock because of the thermal headroom it gives- essentially its the same concept as overclocking in that the silicon lottery can mean CPUs can be better than their factory tuning because Intel is hitting the lowest common denominator in the stock config.

I have used this to moderate success on a 8th generation mobile Xeon to drop the temps ~7C under load, and get the system idle from 6w to 4w (going lower would have been really hard as at that point the CPU was responsible for very little of what remained).

Undervolting is not the same as downclocking, it is supplying less voltage which has a strangely profound impact with no performance loss. However your system can be much less stable.