Originally posted by: davidrees
Multi GPU and Multi CPU are not at all the same.
GPUs run highly parallel, highly repetitive abstracted code and they all run it a little differently. By that, I mean the shader output from nvidia and ATI will always look a little different. On the other hand, if you are running code on a CPU, the output has to be consistent and predictable.
GPUs render as many frames and as much detail as possible in a specific time window. CPUs do the opposite - they use as much time as needed to execute specific instructions (generally).
If you want to do major rendering, why not just use a lot of machines? Don't they still use render farms? Would not the best solution be the most calculations per second per dollar? With energy and cooling costs possibly factored in?
You can build a single processor i7 system for under $1k - great, stack them floor to ceiling. Would you pay $3200 for a dual processor i7 system? It would save space and might save some power, but it does not seem like the ideal approach to me.