According to post quoted below, CineRender is a separate, 64-bit multicore app running in parallel to VW. Presumably, that means it's running in its own memory space and can address as much RAM as is available. That suggests that RW operations would benefit from more RAM, though VW itself is still limited to 2.5 (REALLY? STILL? What's up with THAT?) Gb.
-- source: Renderworks 2011 or 2012, iMacs, memory, and 64-bit addressing