Can someone explain to me wich CPU  I have to choose for Primecoin mining and why?

AMD Vishera FX 8320 - http://www.cpu-world.com/CPUs/Bulldozer/AMD-FX-Series%20FX-8320.html

Intel Core i5 4570 Haswell - http://ark.intel.com/products/75043/

I have to pay 200$ for each, the price is equal so wich is better?