What GPU and CPU is ideal for Penetration testing role job?

[Srazario]

I want to build a workstation to polish my Pen test Skills for my Security Analyst job interviews and want to have something powerful to do the all Security related work. so I want to know that what GPU and CPU is better for such Cracking passwords and hashes plus can also handle serious workload?. Are professional GPUs better for hacking sort of work or the Gaming GPUs?. I also want to know which CPU is better to go for Xeon or i7 extreme?.

Thanks