The CF card is not used as RAM. You can set up directory heirarchies like in XP. Although the WM5 File Explorer can do this, I find its single pane interface to be less than optimal.
I use Resco Explorer, it's a great program that builds many more options into tap and hold and allows panes for browsing like XP's Explorer program. It costs money though, if you want something for free that's a little better than the built-in File Explorer you could use Pocket Explorer. It's free and available
here.
