Mem usage?

[puelly]

I have been using top and more recently munin to monitor the mem usage on a system that I have. The usage is usually around 90-95% of 1GB even tho the machine does not have much going on. Can someone please clarify what cache memory is being used or what exactly is taking up the cache mem listed in orange below. or how I can fine what is taking up the cache.

[bodhi.zazen]

Memory management is different on Linux then say Windows.

The saying is unused RAM is wasted ram.

some helpful links :

http://gentoo-wiki.com/FAQ_Linux_Memory_Management
http://forums.gentoo.org/viewtopic-t-175419-postdays-0-postorder-asc-start-0.html?