I have wrestled with this problem for a couple of weeks now - I thought it might be caused by a third party software (uinstalled it to test), then thought it might be Powerpoint 2013 and the graphics card (AMD Radeon) - took recommendations to disable hardware acceleration in Powerpoint. I even doubled the memory on the system from 4 to 8 gb.
Still getting memory leaks - and by that I mean that the system will show in the task manager that memory being used is flatlined at 6-7 gb and the system is unresponsive after sitting idle for 24 hours doing nothing.
If it's not a software package causing the problem...and only typical things running in the background (McAfee that's about it) - screen shot attached.
I have already rebuilt the bootcamp partition also, and reinstalled all bootcamp drivers. This is a Macbook Pro 15" Early 2011.