How can I optimize cooling for my Mac mini setup?

While the Mini does have fans for cooling, it also makes use of the its case for additional cooling since it is made of metal. Putting a covering over that has effectively put a coat on it keeping it just a bit warmer. For light use of the Mini it may not matter but when under heavy load, every little bit of heat dissipation matters. If the Mini's case was not also part of its cooling, it would have been made of plastic to save costs.

woodmeister50 is spot on. In addition to fan cooling, the outer aluminum case acts as a heat sink.

To prevent over-heating, you should remove the Mac mini from the hard case before using it.

I have no technical information to prove that what you are doing is wrong but it just does not sound like a sensible idea.

Putting a piece of machinery upside down in an enclosed space seems completely wrong.

Why are you doing it?

How do you get the cables in and out of the box?

Could you supply a photo?

Well....

My degree is engineering with a specialty in thermodynamics. I have a new m4 Mac mini. The following are my thoughts based on the short experience with it.

The M4 pro Mac mini cooling system is fine for almost all tasks. But at very, very heavy continual tasks, such as gaming at 60 FPS and 5K resolution, the cooling is not sufficient IMHO. (Tried it. It works fine, but the top surface reached 120 F.) No, the computer will not fail, but it was too hot in my opinion.

So.... Do not wrap the Mac mini in anything. Do not turn it upside down. Do not block the air flow going to or from the fan. Do not set stuff on the top surface. The metal surface is an integral part of the cooling system. Doing those things alter the cooling system.

By the way, regarding gaming, just dropping the FPS from 60 to 30 pretty much resolves the high temperature.

Another option is to install an app that lets you control the fan speed. On my Mini M4 pro even under heavy tasks the fan speed can reach >2500 RPM but when I use my app (TG pro) I can make the fan speed up to 5000 RPM which lowers the temp quite a bit.

I run Windows through Parallels and one game I have is Rail Simulator, and the mini does run a little warmer. One thing I decided to try for extra cooling is placing it on a laptop cooler. I had one that I'm not using and it helps a bit. Be anxious to see what others think of that.

Is this what you are using as it is only intended as a carrying case?

Many have mentioned that the case acts a heat sink.

For that to work, your Mac Mini needs complete air flow around it—with no obstructions.