This question has been asked several times all across the internet, but without any satisfactory answer to date so I'll try again.
For almost two years now, I've been noticing ridiculous memory usage by explorer.exe . I have gone through disabling shell extensions, malware checks, and the issue persists.
Basically explorer.exe just consumes RAM like the memes say about Chrome.
In Process Explorer I can see that several little programs and applications, like Chrome, are nested below explorer.exe, however killing those does not affect the working set of explorer. Scrolling through the loaded libraries of explorer in Process Explorer, I can't find anything that seems out of the ordinary, like extreme RAM consumption or massive amounts of instances. The biggest things here seem to be the Nvidia drivers, totally on a private WS of ~800kB.
Process Explorer:
