Thanks for bringing this up and for your detailed observation regarding the ASD fans.
First, my setup is a Mac mini M4 connected to a ASD. The biggest problem is the difference between setups ASD with a Mac mini and setups ASD with a Macbook. Some users just connect the Macbook with the TB cable to the ASD so it is getting charged via TB from the ASD power supply. In this case it seems to be just logical that the ASD needs to cool his power supply and the ASD fans run all the time.
After reading how to setup clamshell mode (I don’t have or use a Macbook) it seems there is no need for the ASD to deliver power to the Macbook because it's connected to his own power supply. So if this is correct, the conclusion could be, a Macbook in clamshell mode connected to a ASD should behave like a Mac mini connected to a ASD.
Lots of if, could and would. You can read details about behavior of the ASD (with Mac mini) in this thread.
https://forums.macrumors.com/thread...s-are-in-sleep-mode-since-macos-15-4.2457769/
There are still some important differences between Mac minis and MacBooks because MacBooks have additional and/or other settings in energy settings, what makes it impossible to compare a device behavior even with the same settings because there is always the chance that one setting the other devise doesn’t have makes that tiny little difference why or if the ASD fans keep running.
In fact I’m watching the ASD fans since December 2024 and it is 100% confirmed from other users, the ASD fans changed behavior right with / after the macOS 15.4 update.
Can you provide us a screenshot of your energy settings and what macOS you use (not sure what OS Apple did put on that brand new device or if you use any beta) Also pleas check the ASD firmware version.
I wasn’t able to find any Mac mini user with macOS 15.4 and later where the ASD fans stop after the background tasks of the Mac mini. Did not take any attention to Macbook users because of the mentioned differences.
We need to get rid of this unnecessary wear and tear. If the ASD Display is black and no power gets delivered to an other device, there is absolutely no reason for the ASD fans running.
It is interesting you found your ASD without fans running this morning. Need to know more about that. Thanks.