@pwm @bajax @icedquinn an index tray with 4 cpus going full bore is over a kilowatt of pure heat generation from the TDP of the processors ALONE. One rack contained like 5 bays of 28 computers each on sliding trays with power distribution in the ceiling backed up to suckers that pulled cold air through the computers from the aisle and exhausted it into a massive heat exchanger that used open-air evaporative cooling with atmospheric exhaust. We are orders of magnitude past "a bigger radiator", the thermal permittivity of aluminum is insufficient to cool that kind of thing if you were to scale a radiator large enough. You'd have to make your pump out of unobtanium to move that volume of water through the system