For lots of processor-heavy things (mining bitcoin, rendering animations, what have you) it isn't especially crucial.

The key thing about those isn't that they're processor heavy; it's that they're very parallelizable, and have minimal data dependencies between subtasks. For an example of something that isn't like this, calculating scrypt hashes is very processor-heavy, but is provably Hard to parallelize.

I suspect that most interesting calculations will bottleneck on communication latency.