If you want to build a serious rig - new CPU

[whs]

This looks like one of the fastest stock CPUs on the market right now. And for $349.99 with promo code EMCYTZT4938 it is reasonably priced. You may want to use a more potent water cooler though. And your electric bill may go up a bit.

Newegg.com - AMD FX-9590 Vishera 4.7GHz Socket AM3+ 220W Eight-Core Desktop Processor - Black Edition FD9590FHHKWOX with Liquid Cooling Kit

 

[archer]

CPU surely is priced at a reasonable price. But, with this kind of monster we would require a good MOBO to handle it's power. And that can be expensive.