I need help making the best possible computer for UE4

Ok… I finally decided to order a brand new system to run UE4 on! Thanx again mikepurvis, for guiding me in the right direction!!!

Alienware Aurora: ALX Matte Black 875W Chassis; Intel Core i7-4930K Processor (6-cores, 12MB Cache, Overclocked up to 4.1 GHz w/ Turbo
Boost); Memory : 32768MB (4x8GB) 1600MHz DDR3 Quad Channel; Hard Drive: 256GB SSD + 1TB SATA 6Gb/s (7200RPM) 32MB Cache; NVIDIA GeForce GTX 780 3GB GDDR5; Windows 8.1 (64Bit) Dutch

Has anyone tried using a setup like this? I’m putting this together for a nephew who wants to use UE4:
HP Z420 workstation running a Xeon E5-1602 @ 3.60 Ghz, 4Gb - Geforce GTX 960, 32Gbs ECC ram (4x8Gb), 1Tb SSD boot drive and a 2Tb storage drive.

Was also considering another system I have laying around, an HP Z800 workstation which I could put in similar parts but this system would be running dual Xeon Quads or 6-cores. Does anyone know if using a system with 2 processors would be helpful? I can’t seem to find anything on the subject.