you will also be using fast memory instead of a scratch drive/array, less need for expensive 8-drive arrays just to get some decent scratch storage to help, that could cost thousands in the past.
Do be sure to point somewhere besides the boot drive for primary scratch, and disable spotlight on the volume as well.
I think even now it can help to have a fast dedicated drive for scratch and I've seen people use a 2nd SSD for that (say your old SSD now that you bought a new faster model).
Also, MPG has a page looking at using 2-3 8GB DIMMs and finds them 15% more bandwidth and faster than their smaller cousins, just don't mix 8's with smaller DIMMs, so you might want to look at going in that direction.