The biggest key to software today is, is it multi-threaded? If so how many threads can the software run on? Right now not much can run on anything more than about 4 threads. Applications like Adobe CS5 can run a great number of threads. Cinema 4d R11.5 starts to support multi-threading but I dont know how many threads it can run on. Odds are you are going to find your best performance with the Intel Core i7-2600K.
Intel Enthusiast Team
Since cinema 4d can support up to 64 threads will it be worth it to get another 2600k? Well that is considering if I built a 2600k machine it would cost around 900-1200. What about getting 2-4 of these: http://www.weirdstuff.com/cgi-bin/item/386075
it is substantially cheaper and seems to give relative performance. So in total I would have 16-24 cores to render with and an additional 8 because of the 2600k. Any suggestions?