Re: MSI Mpower PCI-E slots
More research last night and slot 4 is PCIe 2.0 vs 2, 5 & 7 which are PCIe 3.0. A card in slot 4 will disable the x1 slots 1, 3 & 6 so the above is slightly wrong.
This build is in many ways similar to some coin mining setup. Lots of GPUs for compute on a budget. There must be half a chance I could space cards on riser cables on 4, 5 and 7 if I decide to add another card whilst keep the whole thing air cooled. Water costs too much money and effort. Maybe spread things out on an open test rig and then hide it away in a metal cabinet with a bit of sound damping for good measure. Fire proof!!
Thinking ahead I need a new PSU for this build. I have a 750W XFX Silver spare and would probably look at either EVGA or Superflower Gold rated. Overclockers seem to have an exclusinge on a Galaxy 750Ti Razer single slot so that would be my choice to drive the dual display and can add to the CUDA pool for baking images overnight.