this is what i use as my 2nd system to run 4x wow on it. and the main pc i run 5x wow on it.

old system 4x wow
Intel Socket 775 Rampage formula (i have it for 8years now)
intel Q9550 quad processor
Radeon msi R7 240 2gb ddr3
8gb ddr2

mainsystem 5x wow
intel i5-4670 CPU @ 3.40GHz, 3401 MHz, 4 core('s)
16gb ddr3 1666mhz
AMD Radeon R9 270x 2gb
AMD Radeon R9 270x 2gb crossfire