I need to build a professional workstation for rendering in 4k. I want to use the latest Xeon processors. I am not sure about spending extra for the professional graphics cards especially when I could get the r9 295x2 with plenty of Vram and even Xfire it. I understand there are performance optimizations for the Quadro and FirePro cards for C4D and such, but for the price I could get more performance with 2 cards. Also are there any Xeons with DDr4?