True better take max 4 gpu. More is ineffective. I also throw some gpu to ltc 
Ok, well i guess i can do 2 x 4 systems - keep things simple.
What sort of GPU and PSUs do you use? I take it for a 4x system i'm wanting a 1200watt good brand? Also do you need an active riser for the 4th? OR can you get away with 4 passive risers?