I AM ADDING A 5 LTC bounty to this

The system specs for above, Im helping Pete assemble this rig.

AMD FX 4100
MSI 990FXA-GD80 v2
5x MSI R7950 Twin Frozr 3 Boost Editions
16GB Crucial DDR3 1600
Lepa G1600 PSU
2 - 1x to 16x powered risers (I have more on order)
and a bunch of 16x to 16x non and powered risers

I have tested the voltage levels, with a power supply tester all are within spec
I am just running the cards when I got 4 to work in CGminer at stock speeds.

we are running Windows 8 x64
I haved tried AMD 12.8, 13.1, 13.4 drivers
AMD SDK 2.7, 2.8
CGMiner 3.1.1

I have disabled everything that is not needed in Motherboard BIOS
I have jumpered the 1x to 16x Risers, and I have tried with a 16x to 16x jumpered,
every conceivable combination of Riser cables in the PCIe 16x and the PCIe 1x slots.
I have the cards in my test bench raised above the motherboard, they are close together for right now, but I will build another chassis to spread them out.

In referencing the cards

#1 is in the Primary (Top Most) PCIe 16x slot
#2 is in the Seconday PCIe 16x slot
#3 is in the Third PCIe 16x slot
#4 is in the Fourth PCIe 16x slot
#5 will be used in one of the PCIe 1x Slots


I start out with 2 cards in the primary 16x slot and secondary 16x slot and once that works I add the 3rd card in the 3rd 16x slot
The bottom slot (16x) seems to be a pain, as getting it to show up in Device Manager sometimes it does and doesn't, after I get the third card to work
I have got the 5th Card in the top most PCIe 1x slot to show up in Device Manager, but the 4th card wont show up, and or vice versa

Before I try CGminer I look for the cards in Device Manager, and we Pete and I have read tons of Posts,