i have 24GB on Main pc i use for 3D Animations,Gaming,movies,VMware7 or all at once and my windows after it loads is at 769MB ram loaded (Disabled alot of windows features and Services) using AVG Tuneup 2011, Tuneup utilities 2010 Tweak 7 and sticking to Windows security essentals. But after i start using it its sits @ 1.2gb-1.4gb Steam,Xfire,Raptr Everest Ultimate,VMware Loaded MAC OS X Leapord and Windows 98SE For older apps and DOS games and i allways have MVware going on another screen so total after all is loaded its 2-4GB
and for system testing/Cleaning Tuneup utilities 2010,Windows Memtest, and a Bootable USB key with some classic and new DOS testing apps (Windows server 2003 X64 ad Linux DLS with apps also) USB Key 16gb USB3.0
over the last few years i have use alot of rame over afew pcs and found the ones with Corsair or Kingston failed first and fround GEIL and OCZ realy good in my opinion!!
I Love playing with CRAP!!!!
And for system repair i have setup a server pc and a USB Key with Windows OS installer for windows XP SP3, Windows server 2003 X64, Windows 7 32bit and 64bit