What is it about TS4 that makes a computer run so hot?

The Sims is very much a CPU hog.... I remember the Sims 3 and 2 also ran my computer(s) much hotter back then too, and I've always had the latest-greatest gaming computers with massive cooling systems etc throughout all the years (I take my gaming very seriously LOL). Sims 4 doesn't seem to be any better, even though this one is supposed to be minimized for lower-end computers... but it still sucks a ton of CPU usage just like the previous generations.