In Vray there is a very effecient combination of “Light Cache” for primary bounces and “Irradiance Map” for second.
Now there is talk of a (well into the future) implementation of “Irradiance Cache” in Yafaray due to GSOC and Brecht has talked some of “Irradiance Cache” in Cycles.
1: What is the difference between: “Irradiance Cache” (yaf +cycles) and “Irradiance Map” (Vray) or is it the same?
2: What is “Light Cache”? (combination with Irr. Cachce in Vray)