Eating up my Ram!

I have 1gb in my girlfriends iMac 20" 2.0ghz. Sometimes, when nothing is going on the Ram will say 100mb available ... whats going on?

Shouldn't it say at least 800mb free?

Has Leopard got default settings that reserve to much memory or something?

Thanks for any advice. Sometimes the system can hang for while or takes a while to boot up.

can't really give you expert advice other than 1 gb memory is rather minimal and i would advise your girlfriend to update to 2 gb asap. the machine will run that much faster.

http://docs.info.apple.com/article.html?artnum=107918

If you have lots of Blue and Green, then you are fine. Installing more RAM won't make a bit of difference in that case.

If there is mostly Yellow and Red, then you might need to add some more RAM.