I have a problem with my memory on my macbook 13" Unibody 2010. I upgraded the RAM to 5GB from 2GB a couple of months ago. Ever since I've done this the memory seems to max itself out very easily, even with all applications closed. I downloaded an app from the app store, called Boost&Memory, which lets me monitor the usage or memory. I can use to 'free up memory', but it seems I have to do this all the time.
Hope someone can give some advice or help on this.