Todd Kopriva has the announcement at his blog. Looks like Ray Tracing fixes, and Kepler updates. Wonder if those would translate to a Mac with a Kepler card in it? Anything with CUDA updates is good in my opinion.
Actually reminds me that I need to replace my Quadro 4800 with my GeForce GTX 285, which the recent NVIDIA update should have helped with the crashing issue I was having.