[morsch]

They were being used for CPU cooling by enthusiasts in the early 2000s, in combination with water cooling. Having a peltier device in it adds so much heat to the overall system that it's really only a measure of last resort in terms of bulk heat transfer.

[creshal]

You also have to be careful that the cold side doesn't get so cold that water condenses around it and into the CPU socket. That was an expensive mistake.