Gigabyte H61M-DS2H motherboard only recognizes 3/4 gfx cards

[BONER_PATROL]

I'm running Xubuntu 12.04 x64 with 4 7970s connected with pci-e extender cables on a Gigabyte H61M-DS2H with a Celeron G540. Three of the pci-e slots will work fine (x16 and 2 x1) but it doesn't seem to want to recognize the x1 slot right next to the x16.

I've swapped cards, extender cables, and power cables around in different permutations, but aticonfig --adapter=all --get-odgt always returns ERROR - Get temperature failed for Adapter 2 - AMD Radeon HD 7970 Series, regardless of what order I have the cards/cables in.

Running aticonfig --list-adapters shows the 4 cards.

Since I've swapped everything around, it seems like it's either the motherboard or maybe the OS. I've checked for options in the BIOS, but there's nothing that seems to deal with the pic-e slots.

[John (John K.)]

Whitelisted and moved to Mining Support.

[ssateneth]

Did you try shorting pci-e presence pins?

[BONER_PATROL]

Yes, I tried shorting those pins last night as per the images below, but it had no effect. I changed some BIOS settings (disabled onboard video, switched PEG:PCI first) but that didn't help either.

http://blog.zorinaq.com/images/pcie-short-schematic.png

http://blog.zorinaq.com/images/pcie-short-photo.jpg