Out of memory

I am working on a 20 track project (with stems) that includes multiple instances of a few plug-ins but with different settings. When I try to render one song (along with its separated parts) The processing starts, gets to about 0.6 seconds and then I either get a message saying ‘Out Of Memory’ or I get a long list of the plug-in that has crashed.

Does anyone know what the problem might be?

What plugins are you using? Some plugins use unfortunatly lots of memory.

The problems seem to occur from Waves and Izotope plugins. Strangely I can process tracks if I don’t have anything in the master section where I have one instance of Izotope ozone 4 and a few Waves including L3 multimaximizer. So I have gotten around the problem by processing the montage without any master plugins then processing those ‘mixed’ tracks with the master plugins. I hope that makes sense!