I was wondering what the maximum power draw you have seen. Do you monitor your energy usage during normal use and during a party with all machines buzzing.
I suspect though that even when the game machines are running they probably don't draw all that much power compared to the HVAC. We seem to have ~10-12kW going to HVAC throughout the day... this feels broken to me (these are supposed to be high-efficiency heat pumps and such) but I haven't been able to figure out what's wrong yet.
Whereas if all the computers were drawing the theoretical maximum their PSUs support (750W each) that would be 15kW, but in practice I suspect they draw a small fraction of that most of the time, even when in-game.