Do some companies throttle servers at times of low use to save power?

Solution 1:

Is throttling server performance ever used by companies to conserve power?

Actually that is done all the time: all modern systems use power management und dynamic clock control to conserve power and reduce cooling.

However, this is a dynamic process, controlled by processing demand. As soon as there's processing demand the clock ramps up, so you'll barely be able to measure the tiny bit of latency that causes (in the order of microseconds).

In practice, you can completely ignore power management.

(I've simplified somewhat - in reality it's a bit more complicated factoring in processing demand, temperatures, thermal envelope, power budget, at even more details.)