I didn't ask you earlier how much free HDD space you have & how much ram. Under apple icon on toolbar, you'll see an option either called About this mac or System profiler. Select it & then select More info ... And that will show you your hardware set up.

For most programs, OSX system will give each program as much ram & Virtual memory as they need at a given moment. In most cases there's no way to control this (unlike in OS 9 & earlier.) Virtual Memory (VM) btw is when ram is stored on the hard disk drive (HDD) instead of actively in ram. LW tends to use a lot of VM.