Help -- 6x 580 , one card runs at 300/300 clock when 4 or more GPU plugged in

Hello miners,

I have 6 rx 580 cards plugged in. The problem I am running into is that one card (random card is picked on boot) will only run at 300/300 clock when 4 or more cards are plugged in. This results in the hashrate dropping to 4 MH/s.

4x ASUS 580 4gb
1x Gigabyte 580 8gb
1x MSI 580 8gb

All cards individually tested, (1 plugged into the system) work perfect.

While testing,
Boot 1 with 6 cards. a 8gb card with 4mh/s at 300/300 clock
Boot 2 with 5 cards (excluded a 8gb card) = a 4gb gpu with 4mh/s at 300/300 clock

I have uninstalled an reinstalled drivers multiple times.

When I have 6GPU, the 2nd slot (x16 w/ powered riser) is the card that gets stuck at 300/300.

When I disconnect 2nd GPU slot (5 total cards), the 5th slot GPU gets stuck at 300/300.

When I disconnect 5th slot GPU, the 6th slot GPU gets stuck at 300/300

Throughout this whole process I am incrementing PCI/PCIe Bus Errors in HWiNFO.

Any thoughts on this? Any help would be much appreciated