Exactly this. Makes no sense for a single desktop computer, but when you have a huge room filled with servers, it's a lot more efficient to pump cooling water a

Exactly this. Makes no sense for a single desktop computer, but when you have a huge room filled with servers, it's a lot more efficient to pump cooling water around than blowing a huge amount of air around. Also air cooling a rack full of equipment is getting more and more difficult as power densities increase, which is one of the main motivations of going to liquid cooling.