I didn't assume, the question contained "CPU-heavy", and the answer is relevant because it's a common misconception that you can make up for a slow language with parallelization, but you can't. If you've got a CPU-heavy task, you will find in practice that even using a lot of threads you'll be lucky to get even a 3x speedup on clock time, unless your problem is 100% strictly embarrassingly parallel. (I've tried a few times, which is where the 3x comes from. It's all I was able to get and my tasks were very close to embarassingly parallel, but the cruel nature of Amdahl's law is that it takes only very slight non-parallel components to wreck your speed.) It's not a viable solution in practice.