The dock or the laptop? Neither are particularly warm when running let alone sleeping. Only time the M1 was warm enough to spin the fans audibly was while using at full load and charging the battery from a nearly dead state. Regular full load use doesn't bring about any fan noise, though the bottom gets a bit warm. The dock fan would come on when my old 16" MBP was running full load, probably because it was supplying the rated 90 watts but I haven't heard the fan spin up with the M1 attached. Just touched the dock, cool to the touch except the Thunderbolt module which I would describe as slightly above room temperature. Currently have a 4K monitor over displayport, external thunderbolt SSD, large RAID array, ethernet, a few other USB devices, and the laptop connected.