I'll just add, don't panic about massive ram usage. Its linux and thats normal. It manages RAM a whole lot better than windows, and in fact, one of the reasons linux is so good is because it uses the ram rather than pushing it all to virtual memory or "swap" like windows does, there fore making it quicker.

Sounds like to me you've got a lot of junk floating about. If you have extras-devel and extras-testing on you have been warned what apps from these repositories can do to your device.