Motherboard of choice for 6 or more GPU's

[boozer]

I'm building some more rigs.... Just wanted to figure out what today's motherboard of choice was for miners using 6 or more GPUs.  I would like to get 7 or 8 on a board but wasnt sure what boards support it.  I dont think there are any boards that support 8 gpu's, but let me know if you know of one.

Thanks!

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[cptmooseinc]

You're not going to really get past 6 GPUs with anything standard. You'll need a server rackmount to go past 6 GPUs I think. You can attempt it with the Gigabyte UD-7 motherboard and some powered riser cables for 6 GPUs. You -NEED- to make sure that the GPUs you are buying are voltage unlocked. You'll also need a 1600W PSU. The reason I say you'll need the cards voltage unlocked is that 5 7950 GPUs will use every bit of 1500W of power, so if you want to go to 6 and use 7950s, then you'll need to undervolt them to get the 6th card on.

Other GPUs may use less power and might not need to be voltage unlocked, but I don't know anything about those.

[jambaman42]

I'm not crazy knowledgeable but 6 is a lot of cards for one motherboard. Going 2 sets of 3 may be in your interest or even 2 sets of 4 if you want 8 total cards. Most PSUs just won't be able to pump out the power you need to power that many cards.

[CartmanSPC]

You can attempt it with the Gigabyte UD-7 motherboard and some powered riser cables for 6 GPUs.

I looked at using the Gigabyte GA-990FXA-UD7 myself but I believe it has a supplementary SATA power connector on the motherboard to adequately power 4 way SLI.

Cablesaurus states on their powered extenders:

"For use only with traditional motherboards using only a CPU/ATX motherboard power connector, and no supplementary SATA power connector on the motherboard"

[Marrs]

I'm building some more rigs.... Just wanted to figure out what today's motherboard of choice was for miners using 6 or more GPUs.  I would like to get 7 or 8 on a board but wasnt sure what boards support it.  I dont think there are any boards that support 8 gpu's, but let me know if you know of one.

Thanks!

The MSI Big Bang Marshal has 8 PCIE x16 slots.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130595

[cptmooseinc]

You don't run the cards in SLI or Crossfire modes. My UD-5 has the standard power plug plus the 8 pin adapter and it works just fine running 5 7950s on Windows 8 using the scrypt fork of GUIMiner. I just had powered riser cables come in today and am going to swap them out for the standard ones I have in there to see if it increases my kH/s as I believe the memory for the cards pulls its power from the motherboard and not the power connectors on the card. Hopefully then, I can decrease the powertune.

[boozer]

I have 6 cards per rig, 3 of them on powered risers... two rigs... 3 Seasonic 1250 Watt gold power supplies.  Each power supply powers 4 cards.

I have the Gigabyte 990FXA-UD5 and the MSI 990FXA-GD80 and they both can handle 6 GPU's I believe (still waiting on 1x risers to arrive).  It looked like they had been out for awhile so I didnt know if there was anything better on the market that most people were using or not.

[boozer]

I'm building some more rigs.... Just wanted to figure out what today's motherboard of choice was for miners using 6 or more GPUs.  I would like to get 7 or 8 on a board but wasnt sure what boards support it.  I dont think there are any boards that support 8 gpu's, but let me know if you know of one.

Thanks!

The MSI Big Bang Marshal has 8 PCIE x16 slots.

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130595

Thanks, but anyone got this one working with?  And are there any out there that aren't discontinued 

[cptmooseinc]

This has 7 PCI-e x16 slots: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157327

You'll need voltage unlocked cards (try the Sapphire 7950 4L's as they should be) and a 1600W PSU. Running Ubuntu you should be able to get all cards running if undervolted. I suggest powered riser cables as the motherboard will definitely need help supplying power to these bad boys. It spreads the motherboard too thin if you try and pull all the power necessary for the memory from just the board.

If you're mining LTC, you need at least 2-3GB of RAM per card, so plan on at least 24GB of RAM (might as well do 32GB).

[kendog77]

"If you're mining LTC, you need at least 2-3GB of RAM per card, so plan on at least 24GB of RAM (might as well do 32GB)."

I often hear people say this, but it's simply not true. I have a rig with 4 gigs of RAM mining litecoin right now with 4 7950s running at 600k each (2400k total). Perhaps it used to be a limitation, but 4 gigs of RAM works fine mining litecoin using Ubuntu 12.04 with cgminer.

[Vorksholk]

You can always use multiple PSUs, too.

[boozer]

"If you're mining LTC, you need at least 2-3GB of RAM per card, so plan on at least 24GB of RAM (might as well do 32GB)."

I often hear people say this, but it's simply not true. I have a rig with 4 gigs of RAM mining litecoin right now with 4 7950s running at 600k each (2400k total). Perhaps it used to be a limitation, but 4 gigs of RAM works fine mining litecoin using Ubuntu 12.04 with cgminer.

If one uses Reaper to mine LTC, you need a lot of RAM, but you are correct that cgminer does not use much RAM at all when mining LTC.  I upgraded RAM in several rigs thinking I would need it but my 5 x 7970 rig only uses just over 1 GB of RAM when scrypt mining, so the rest of the RAM I bought is wasted, lol.  It gets about 3.45 Mh/s on Scrypt with cgminer using a tad over 1GB of RAM.  It does use a lot of video memory though, but hey, that comes with the cards

[boozer]

This has 7 PCI-e x16 slots: http://www.newegg.com/Product/Product.aspx?Item=N82E16813157327

You'll need voltage unlocked cards (try the Sapphire 7950 4L's as they should be) and a 1600W PSU. Running Ubuntu you should be able to get all cards running if undervolted. I suggest powered riser cables as the motherboard will definitely need help supplying power to these bad boys. It spreads the motherboard too thin if you try and pull all the power necessary for the memory from just the board.

If you're mining LTC, you need at least 2-3GB of RAM per card, so plan on at least 24GB of RAM (might as well do 32GB).

A little on the pricey side for me, i can just buy another mobo/ram/cpu and psu for that   Thanks though, thats the type of stuff i was looking for.

[ButchHashidy]

I think the best you can do with consumer grade products will be 4 dual slot GPU's on a motherboard with 7 or more PCI-X slots.  Keep in mind every card will require the spacing of two slots.  And as someone else already pointed out, you're going to run into heat problems.  This is the motherboard I was looking at.  You'd be able to fit 4 cards in here with a large enough case:

http://www.newegg.com/Product/Product.aspx?Item=N82E16813130626

If you're rich, there are server grade, rackmount solutions.  Some aren't as expensive as you'd think.

[Benjie]

Can anyone shine in with boards that accommodate 4 cards without risers (just sitting on board)..
The ASRock 970 Extreme4 should be the most efficient after lots of searching, but i cant find it in my country..

[CartmanSPC]

I have the MSI 890FXA-GD70 on it's way since I got it for $59.90 after rebate. It has 6 PCIe slots. This MB has been discontinued so you will have a hard time finding it. I was lucky to find one.

If I had to choose something else I would look at:

MSI Z77A-G45   LGA 1155    7 PCIe***   $114.99  after  $10.00  rebate card at newegg

Searching the forum didn't find much on the Z77A-G45 though so I don't know how well it works for mining.

Don't know of any MBs at a reasonable price with 8 PCIe slots

[bcpokey]

There is little practical upshot to stuffing 8 physical cards on a single mobo rather than 2x4, except potentially a savings of 100w or so for the extra system. And if you're running 8x200w gpus, that's a fairly paltry savings.

[bitrocket]

Here's a list of motherboards from other threads that are known to work with 4 or more GPU's

known to work
-------------
5 GPU - ASRock 970 EXTREME4 ($145)
4 gpu - Asrock 970 Extreme3 ($99)
4 gpu - Gigabyte GA-970A-D3 ($104)
7 gpu - MSI Big Bang-XPower II ($369)

power supply limitations and airflow/overheating are the biggest concerns in 5+ card systems.

add2psu sells a gadget to link two or more power supplies together. If space isnt an issue, two smaller power supplies may be cheaper than one big one

[boozer]

Thanks everyone!   I got my risers in today and got 6 7970's running on my MSI 890FXA-GD70 boards.  I have a new MSI 990 that I'll try it on next.

[cptmooseinc]

What kind of PSU are you using? Or are you using 2 PSUs? The 7950s use like 275W each at stock 1.25V. I've got 5 GPUs running on Windows 8 but I don't believe the 6th will go without a 2nd PSU.