I've had my macbook pro for about a year, and just for the last week or so I've been having this problem. I have 8gb RAM, and it's always been the case that I have about 4gb free. But recently, it just keeps dropping slowly but non stop until it's all the way down. I use a RAM cleaner (icleanmemory), and it brings back about 200mb, but it just drops right back. When I check Activity Monitor, it says a lot of it can be accounted for by Chrome, which has like 10 different renderers sucking up ~30mb each, so I restart chrome and pretty much right away it starts to dip again. Any ideas what this might be? Thanks for any help, much appreciated.