ive never understood memory recovery programs as they use memory themselves. so i dont like them too much. your system caches alot of memory so programs open faster, etc., also the more memory your system has the more memory apps will use. like firefox on my work pc with 512 memory uses only like 10 megs of memory but i have a gig of memeory at home and its using 40 megs, it takes up more to run better.
but its mostly your system cache, which isnt a bad thing, i have a 1gig and all i have is firefox open and i only have 331,000 megs available, the rest is cached from games and apps i previously used.