Need help to build my first hash cracking machine

[mastercracker]

I am not an expert but I would build my rig differently. First, I would go for AMD CPU. You can get a quad core for 81$ instead of 200$. Corresponding motherboard would be the same price or cheaper with 2 pci-e x16 slots for your 2 GPUs. Instead of 1 big PSU, you could get more power with less money by using to smaller PSU (Corsair HX750 for 90$ for example which is 80+gold). With the money saved, I would go for 7970s instead of 7870s.