Hope you don't get Chrome to save your passwords

Problem??
I use HEM, table ninja, YouTube, stars, dtd client, and a few other bits n bobs.
But its the 'post session' status of still using 5Gb of the 8 available that confuses me. I have more than once, closed down everything and checked task manager to find only <1.5Gb of accountable programs. However 4/5/6Gb are in use.
Its like I need a way to 'flush' the RAM....

because of the restarting, im toying with the idea of a tiny SSD just for boot up/ reboot.
Thoughts?