That mainboard has only 4 PCI-express slots (1 x16 and 3 x1, there are 2 legacy PCI slots that are useless for mining). Z97 chipset should have enough PCI express lanes to run 6 to 8 GPU, but you will need some kind of PCI-e expansion board with more slots in order to get all the slots.  I don't know if those boards are realiable enough for a rig, maybe someone could tell us about those boards.



2000 watts should be enough for 6 gpus + a pico for the mainboard+cpu+hdd. Correct me if I am wrong, but i think you will need this.
You will need some 6pin to 8 pin adapters if your PSU has only 6pin connections, and each GPU will use 2: a 6(to 8 pin) cable for the GPU and a 6pin for the riser. So for 6 GPU you will need 12 PCI-e connectors in the server PSU breakout board plus one more for the pico. You could save some connectors using some 6pin PCI-e to Dual 6pin PCI-e cables, so you will end using 1 6pin PCI-e connector to power 2 GPU risers, so a 12 PCI-e 6pin breakout board will be enough


Has anyone tried to build their own 6 or 8pin PCI-e connectors? If so, where can I buy the connectors at a right price? Searching ebay bring me some expensive results