CPU and RAM should be fine for retail (DX11 Legacy) or classic [edit] provided you're not capturing video and watching Netflix and etc. I'm still running 5x 1080p clients on a 6700K non-OC, though I do have 32GB RAM and a 980Ti. Have a search around the forums here for "slot swap macro renderscale" where you can dynamically change the graphics detail levels on clients every time you switch leaders. It makes a hell of a lot of difference in terms of your main window's performance.