Clarification on OS X RAM usage

I'm having trouble understanding how all my ram is being used. The applications running don't take up anywhere near 1 GB. Can anyone explain?

Here is the definition of the terms you see:

Wired memory
This is memory that applications or the system needs immediate access to, so it can't be cached to disk. It will vary depending on what applications you're using.

Active memory
This is memory that is actively being used.

Inactive memory
This memory is no longer being used and has been cached to disk. It'll remain in RAM until another application needs the space.

Free memory
This memory is not being used.

The above is a copy 'n paste from a post I saw on these forums some time ago. I found it useful enough that I saved it off. Hats off to the author, who ever you were!

In general, only your Active memory should be considered "in use" by your applications. I am guessing that the "wired" memory is likely mostly OS stuff, plus lower layer support stuff.

Looked at this way, it does more or less add up.

Does this help?

Thanks for the post, very helpful.