So, out of curiosity I decided to take a look at my RAM usage with my windows 7 VM (3 GB RAM allocated) running. I was... surprised to see the results, and I'm wondering why these results are the way they are:
My host machine's (win 8.1) task manager shows the following:
Which really only shows how much of a hog Chrome is.... Anyway, notice that Virtualbox manager is only using 75 MB of RAM. Well, that's reasonable, this is after all only the manager and not the VM itself. But wait, those numbers (even if you add up what you don't see there) don't add up to the current RAM usage (9 GB as reported in the Performance tab). Given that my guest machine is using 1.5 GB right now, one would expect it to be a bit higher up in the list...
Ok, let's try a different tool: RAMMap
First, two more screenshots from RAMMap:
Well, that bit for "process private" looks to be about 3 GB (unless I'm an order of magnitude off with my cursory glance), but still - nothing except Chrome is hogging more than 100 MB of RAM.
Oh, hey, look at this:
Looks like I finally found where it is... but what is this? Does VBox treat the guest's RAM like a file that it just keeps loaded into RAM? Is this... something completely different? Why doesn't windows inform me of this in its regular Task Manager tool?
TL;DR: Windows, y u no show me all RAM usage