I just upgraded from 1GB to 4 GB - a lot faster. Of course the processor move from a single processor G4 (1 GB Ram) to a Mac Pro with two dual core processors (4 GB Ram) helps as well. Incredible fast renderings for me.

But seriously - it is a mixture of Ram and procvessor speed that makes it. And of course scene settings. Experience tells me that the faster you can render the higher render settings you will use - to come back to the waiting times you are used to.

One day your ship comes in - but you're at the airport.