Nothing special really, just a ivy bridge celeron and a z77 mobo with 7 pcie slots. The mobo is a z77a-gd65, but a cheaper z77a-gd44 (i think?) works with 6 cards... Has to be ivy or 6 won't work. There's 3500W of power under my rig now, but two of the supplies are cheap 1000W'ers. They run 6 7950's at 1.125V, but not 6 280x cards at any voltage. I use a EVGA 1500W to supplement the other two supplies. I ordered 1300W and 1000W evga power supplies, one will power the mobo and 3 cards, and the other will power three cards alone. Ought to be plenty of headroom, I expect 275W from each card.
The rig is running xubuntu, as I wasn't able to figure out how to get 6 280x cards running in W8. You have to use the beta 3.11 drivers for Cgminer to "see" these cards, they show up as 7900 series with old drivers but won't ever mine.
Anyway, 3.11 beta drivers from AMDs site work pretty well. I did a bunch of reading on the net, and these settings are the best mixture of what I was able to find. I should say that these settings might be completely useless to you, but they should be a starting point. These cards all act different, I'm starting to think any results otherwise are just gamblers fallacy! Either way, I won't charge you 1 BTC for my config because I'm not that much of a douche

You will need to tweak the GPU clock speed for each card, most of mine are somewhere between 1025 and 1045.


I can lower the fan speed to 80% and still maintain ~75 degrees. I've got some work left to do with ducting and more permanent fan mounting.
thank you very much! i think i will try to copy your setup a bit as it seems to be very nice

. i have ordered yesterday a rig from open openrigs.com and i will order this stuff:
4x Sapphire 11221-00-20G Dual-X amzn.to/1dIoFTp
1x Gigabyte GA-Z77X-D3H amzn.to/1fUdzL9
1x Intel BX80637G1610 Celeron Dual-Core Prozessor (2x 2,6GHz, Sockel 1155, 2MB Cache, 55 Watt) amzn.to/1fUdAyT
1x Corsair 4GB DDR3 1333 MHz amzn.to/1b4NSnv
1x Corsair AX 1200(i) amzn.to/183tRP5
I have somewhere an old 32GB SSD drive or I am thinking about a 16GB USB3.0 stick. I will also add 2x R9 280x and 1x Corsair 1200w later. But still thinking if these PSUs are the right decision. When everything arrives and I start mining LTC i will make some pics. I will also contact you to send you some LTC for your help!