Hm, not sure. I have to admit I'm still somewhat new when it comes to dealing with macs, so I don't know how common these sort of things are, but then again they are essentially the same hardware as PCs these days so their behavior shouldn't be too different.
Anyway, I'm not entirely sure what I can do to help in the case of a freeze, the only thing I could do is speculate based upon what sort of stuff you're doing in the program. Does it happen if you just have the program open (and not streaming)? Or, does it only happen if you're streaming? That could be one way to help indicate whether it's coming from the CPU side of things or the GPU side of things.