At the op you have a shit card it has a higher draw at the riser end.
would have helped me a lot to know you had 5 six card rigs. using 30 cards
here is a suggestion
have a tester rig and run that card in a slot on the tester rig.
the mobo I linked
is good as a development rig
https://www.newegg.com/Product/Product.aspx?Item=N82E16813145007&cm_re=gigabyte_b250m-_-13-145-007-_-Productit will allow you to slot test cards
All true. I started with a single rig and two cards, and simply added cards till it was full. Then added a second rig and split the existing cards between them. Been adding cards to both until they were maxed, and now have parts for a third. I guess it's just a matter of planning and where you are going with it. I prefer planning for the maximum up front so it's easier to expand upon as you go.
Regardless, he's definitely got something wrong in his setup. I would say we need a full parts list to know where to start as it's pretty trivial to run six cards with the correct parts. If he's looking to expand more in the future, then now may be a good time to setup a second rig anyways which would allow additional parts for troubleshooting.
this is the cheapest quality small mobo I know
you can start with 2 cards in the slots
and later add more cards with risers
it can do 2 in slots = 3
it can do 2 in slots and 1 in a riser = 3 card
it can do 1 in one slot and then 3 with risers = 4 card
it is a great trouble shoot board
and it is a gigabyte 250m so it is physically very small
80 bucks
https://www.newegg.com/Product/Product.aspx?Item=N82E16813145007I put this cpu in it
http://www.ebay.com/itm/Intel-Core-i3-6100T-3-2GHz-3M-Cache-DualCore-LGA1151-CPU-Processor-SR2HE-/322490605689?paid 91 for the cpu it will take this one
http://www.ebay.com/itm/Intel-G4400T-Processor-2-9GHZ-Low-Voltage-CPU-Only-Socket-LGA-1151-NEW-/252844237292?nice psu sale so 109
http://www.ebay.com/itm/EVGA-SuperNOVA-220-P2-0750-RX-750W-ATX12V-EPS12V-SLI-Ready-CrossFire-Ready-80-/382026031239?a stick of ram 25 bucks
http://www.ebay.com/itm/Kingston-16-GB-M-2-NGFF-mSATA-SSD-Chromebooks-Acer-/201888633168?5 dollars for the m2 and smOS is free at the moment
so 80 mobo
55 cpu
109 psu plat evga 750 watt
25 ram
5 ssd/os
so 274 for 2 card
284 for 3 card
304 for 4 card you need 3 risers.
now do this with a six rig
85 but out of stock
https://www.newegg.com/Product/Product.aspx?Item=N82E1681313844985 mobo
55 cpu
25 ram
5 ssd os
229 for an evga 1200 watt p2 or
189 for an evga 1300 watt g2
60 for siz risers
so 394 for six cards x 2 = 12 cards at 788 with gold
or 304 for 4 cards x 3 = 12 cards at 912 with plat
so even with 2 six card rigs vs 3 four card rigs the edge just tips to six card maybe not as the six card may run louder and hotter then the 3 four card setups.
you will save watts with the 3 four card card setups.
All goes by the wayside as you expand but up to 12 cards it is very close