Now I don't want to label it "memory leak" per se, because usually in topics with that name it all comes down to old drivers and non-paged pool. And I think I've already passed that point by following most of those advices.
My situation is a bit different. Something is using a lot of memory and it isn't clearly shown in task manager. After a reboot the situation becomes better, then with time gradually the system takes up more and more RAM, even though nothing is really running, and no one is really doing anything with the computer.
Today is a good example: my wife left to work after me and forgot to shut down the PC. No biggie, of course. But when I come home, I see that half my memory is already gone, and that's approximately 7.3 GBs of RAM. I mean, where did it go, who or what used it all up?
It looks like this:
It all just doesn't add up to such high usage. I am definitely missing something here. When I was using Windows 8.1 this would never go up like this. I mean I had 8 GBs then, not even 16.