Wondering which model you have? Is it fanless? I’ve never used until o got my 2022 m2 air. It’s the best computer I’ve ever used.
Before that, 10 years of Mac Pro, and they’ve all been old (2010 models) and fast.
The 2010 Mac Pro doesn’t run macOS 11+, that might be its X factor.
The Mac Pro can run newer os with the help of open core. I can do many things with it like run Mac osX 10.6 using my modern amd rx570.
I can also run macos 12+ which I do. It runs great!
It’s more pronounced while recording but that’s the idea.
The Early 2020 MacBook Air is a joke from a CPU/Graphics perspective - even compared to other Intel Macs.
I still think something's wrong with your computer, as I have worked with multiple of that model and they weren't nearly this bad (even accounting for screen recording) - perhaps your cooling is worse?