@dc42 FWIW, I don't even need to home the printer, just move any axis, wait and then move any other axis. Doing this now, my MCU Temperature was around 25C and, as best I can measure with an infrared thermometer, the drivers themselves never went above around 23C. When I'm not trying to measure temperature, the board has a 120mm fan blowing on it with exhaust holes out the side which seems to very effectively cool the drivers (as reported by the MCU as a proxy).