I use late 2007 Poerbook Pro, which originally had only 2GB of memory, I had to get rid of those 2 and installed 4. It is still not enough and sometimes I am running low on memory. Sats Bar is helpful, but stays in a middle of the screen whether I want it or not. Preferences of it are difficult to open and automatic memory clearing does not always work. Restart and IceClean seem to help.