(one GTX 1070 ~ 1 min)
If you do not plan to use extremely heavy scenes that require a lot of memory, then choose GPU to render. Get the GTX 1070 to render and then you search for the best CPU you can buy with faster and better performance per thread, no matter if it only has 8 threads. You search and analyze benchmarks for Single Thread CPU performance (intel, amd). This to work faster with tasks in Blender, like simulations. Look at the internet more than one benchmark to be sure it is correct.
Edit:
Some simulations in Blender are multi thread, anyway they do not take advantage very well of multi thread, and it is still more important single thread performance for simulations.