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Hello, anyone knows which motherboard can support 4x GPU and does not need shortening the pins, nor using 16x16 risers, but 16x1? And system would detect them all without any issues?

the fxa-ud5 or even ud3 from gb would take it but that proc is a no-go

mrugala, some personal favorites:
AMD (AM3/3+) -Asrock 970 Extreme4 (http://www.newegg.com/Product/Product.aspx?Item=N82E16813157262)
AMD (FM2) -> Asrock FM2A85 Extreme6+ (http://www.newegg.com/Product/Product.aspx?Item=N82E16813157457)
Intel -> MSI Z77A-G45 (http://www.newegg.com/Product/Product.aspx?Item=N82E16813130645)

Note that there are lots of intel options in the Z77, Z87 range due to Intel fully embracing PCIE 3.0.

Any idea if you'll need powered risers or not for that one?  I can't remember when you do and do not need them, been way too long since I've GPU mined.

Thanks

I am running 5 Sapphire 7950 reference blower model cards like this one  (http://www.techpowerup.com/gpudb/images/b1721.jpg)in that board: 3 Sapphire 7950 blower model reference cards inserted into the x16 slots, and 2 up on powered risers.  No issues.

You need powered risers when your pcie pins are overspecced past a reasonable amount due to the absence of the expected 75w from the physical pcie lane.  If you have say 4 290s up on unpowered risers, that would be 75w x 4 = 300w extra being pulled through the pcie pins.  You are virtually guaranteed to blow something up.

More than one 6 pin for powered risers makes sense... when I had a 5x 5830 (I think that was the card) I had some issues because the risers weren't powered.  1500w PSU should be enough to support 4x 280X, right?

1500w would definitely be plenty for 4 280x.  Each 280x won't exceed 300w in a worst case scenario.

1160/1800 exceeds a worst-case scenario.  One doesn't need near those clocks to get ~750khs on a 280x.  

Running 1160/1800 to get the extra 50khs to 800khs = I don't care about performance / watt and probably don't pay much if anything for electricity.

5x 280x on a Gigabyte GA-970A-D3P ($90 @ Newegg). 2x Rosewill Capstone 750W PSUs. Undervolted the GPUs to 1.019V, and getting 3.5Mh/s @ 1250W.

Here's a similar rig, but with 290s. https://bitcointalk.org/index.php?topic=7216.msg4380855#msg4380855

I think im ordering one of these Asrock FM2A85 Extreme6+ to begin my mining rig (begin just with 1 r9 290 card)
and upgrade later.
Can you guys pls tell me, are the components fit together?

http://imgur.com/WSZjQj1 (http://imgur.com/WSZjQj1)

this is my first experiment with mining, i dont look for profit but  i hope to get my investment back one day ;)

Greetings

http://www.gigabyte.com/products/product-page.aspx?pid=4514#ov

4 pci-e 16 in an Extended ATX motherboard. 

lots of fan headers aux power to the motherboard.  this is great with 4 cards.

Seriously? The one I linked is $100 cheaper. Why would you spend more money, buy this one, when they're both going to do the exact same thing?

Thanks for the mobo info. I just RMA'd my asRock 970 ex4 because I couldn't configure 4 or more 280x's on them.

Can you tell me what CPU, and RAM you are running?

I'm building this rig:

MOBO gigabyte GA-970A-DS3P
CPU AMD Sempron 145 boxed
RAM 8gb DDR3 1333Mhz CL9 Geil
PSU 3x Fractal Design Integra R2 750w 80+ bronze
2x add2psu adapter
3x 1x to 16x PCI-E riser Powered
2x 16x to 16x PCI-E riser Powered
2x Aerocool external fan 120mm
1x Pendrive 8gb
5x Sapphire R9 280x Dual X cod. 11221-00-20g

Rig will work on BAMT 1.2 distro, controlled by my desktop via VNC

@crazyates: do you think that my experiment with 3 PSU (2 for 2 vga each, and 1 for 1 vga and mobo) should be good?
i have only a question about it, can the risers be powered by all the PSU or i must use only 1 psu for 5?

I used a Sempron 145 and a cheap 8GB stick on each rig.

I'm using 3 PSUs on my 290 rig, but a 5x 280 rig may be doable on only 2x 750W PSUs.

Either way, I don't think it matters which PSU powers the card, and which powers the risers. I typically put 4 risers on whatever PSU has the least load, and then the 5th riser on the other PSU. I basically do this because our risers take SATA plugs, and our PSU only has 4 SATA plugs per cable. :P

TL:DR Your GPU doesn't have to have it's PCIe plugs and it's riser powered by the same PSU.

Hi, thanks for the info. Did this Mobo also require a power switch? The asrocks had them integrated on the mobo.

Regarding the 970ex4 mobo, I have some problems running 4x R9 280x on it as well. Not sure what the heck is causing the issue, but I'm about one more frustrating moment away from smashing this pile of crap with a hammer and buying a different board (or scaling back to 2 GPU rigs).

You don't need a power switch. We have the BIOS to auto-power-on upon power failure, so you just flip the PSU switch off and then on again, and the MB turns itself on.

You will need to turn it on once, before you configure the BIOS settings, but that's pretty easy to do, using a switch from an old PC case, or just simply touching the two power on pins in the MB header together with something metal, like a screwdriver or a metal pen tip.

Cool, what brand of 280x did you use ?