What’s best for Cubase 8 Pro ?
Quad Core or Hex Core?
Would you prefer an overclocking chip or stock chip?
What’s the difference between the CPUs you are looking at?
What will improve capacity is more cores and/or higher clocks. It comes down to how much are you willing to spend to get them!
Running at stock speeds is likely to keep your system running the coolest, which means your fans can run the slowest possible, so making less noise. However, being able to overclock is useful for when you might just need some extra CPU grunt for a larger project.