It's actually quite cold, if you're thinking of water blocks on the chips. It does fit if you're thinking of air-to-water heat exchangers to cool the hot exhaus

It's actually quite cold, if you're thinking of water blocks on the chips. It does fit if you're thinking of air-to-water heat exchangers to cool the hot exhaust of a google rack before recirculating. Something closer to 30C or even 40-45C (the latter if you're in a hot and humid location like Florida and want to get by without refrigeration technology and just increasing the flow rate/heat exchangers) is more realistic for datacenter-scale component-level water cooling. Yeah, a high-power-density Nvidia chip may need colder water in the 20-30C range, but CPUs and such aren't efficient at the clocks that cause power densities where you need <<40C water. My 5950X is running at ~30C (return from the radiator) water and 4.5 GHz (maybe even a bit more? I don't recall, the heat wave around here is over) on a torture test with Prime95 where it produces almost double the nominal TDP (thermally limited, due to a few hot-running cores and around 80-85C average core temperature on the others). The base clock is at just 3.4 GHz. I see phase-change cooling with nucleate boiling as well as very tightly integrated (liquid) water channels in the future, with the latter thinning out the die to weld or solder a better thermal conductor closer to the actual transistor junctions, with minimal distance to the coolant.