I've been trying to build this kind of rig following vortac's earlier articles. I hope you have better fortune that I with secondhand parts--ATM I can only get a single GPU to run at a time (even on a dedicated mining board--can you have 8+ bad GPU risers?), Win10 cuts off the Wifi at random intervals, and just today the old HDD I was running things from has decided to crash its heads together and quit.