> The 39W max draw probably assumes the display is on?
No, this is the number for the Mac Mini, which is the obvious choice if you wanted a machine for maxing out an M1 24/7. (The Air peaks at about 30W, which it can't sustain for long unless it's in a rather cold environment.) So it has nothing to do with the display's power consumption.
Maxing out just the GPU while the rest of the machine isn't doing much would get you well below 39W, though.
Hmm what if you have the speakers on max volume with pretty much all the other sensors all maxed? Here are a few I can think of: keyboard backlight, wifi, bluetooth, accelerometer, speakers, mic?, camera, proximity sensor, touch id, maxing out CPU, GPU, ML engine, SSD, ram, typing on the keyboard, using the trackpad. Using those all at once must surely draw more than 39 W if not then not using most of them must also mean it probably draws a lot less than 39 W during normal operation.
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