Perhaps 4 or 5 releases ago, Mac OS X did not do.a very good job of garbage collection (GC) - releasing united RAM. I typically have lots of apps open (PPT, PS, Camtasia, browsers). Especially with Fusion, it was easy to run out of real memory. Memory Clean was awesome, and allowed me to get working without the beach ball.But more recently, Mac OS X 's GC is much better. That, along with memory compression and faster SSD/storage, mean that I rarely encounter beach balls due to not enough available memory.