Btw, i recommend sims 4 updater, it loads the newest version and all DLC as crack. Got my 2021 torrent working with the best mods.

Meanwhile, Sims 4 is being nefarious in the background.

Actually all of the game mechanics should be stopped when the game is paused.

The most likely culprit is the graphics pipeline still being busy assembling and sending data to render to the GPU every frame, since even though the 3D world is paused, the thing has to keep on operating because of the UI.

It should be possible to make it less of a problem if the UI you're interacting in during pause is on-screen 2D and all the 3D stuff is fully static (i.e. no autonomous movements such as simulated wind on leaves or running water) but depending on the graphics pipeline implementation being used, it might be too much trouble because you need to somehow have it stop rendering the 3D stuff and only do 2D.

Also, EA being as they are, I doubt the programmers had the time to go after a "cosmetic" (lowest priority) issue that probably has system design implications.

simulating 4 no less

Better than 100% on one and nothing on any of the others.

It should at least use less CPU. What work could it be doing other than playing the music?

Who needs to fix things from the ground up when you can just throw in more and more code! You can just fix it with more code!