Motherboard of choice for 6 or more GPU's

[crazyates]

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.

My 7970 doesn't even pull 275W, and that has a high 1.256V as well. What are you doing to pull that much power per card? All 5 GPUs pull ~1400W at the wall? That's not right.

[cptmooseinc]

I have the Powercolor AX7950 GPUs with a 1600W LEPA PSU and the Gigabyte 990FX UD-5 motherboard. With a Kill-A-Watt hooked up to it, I see a power draw on it of about 1400W. Maybe that was when I had powertune at +20 on it though? I'm redoing that board now as we speak (bringing it up to Windows 8 instead of Windows 7) and won't be having powertune on it this next time. I'll report back once it is up and running. Swapping out standard risers for powered risers to see if the kH/s goes up some with non-powertuned settings. Then I'll attempt to add a 6th card into the PCI-e 1x slot (I have a 1x->x16 riser) if all goes well.

This milk crate is getting tight on space! :p

[mccminer]

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..

I'm using the ASRock 970 Extreme4 in one of my rigs, and the most you can get without risers is 3 GPU's.

[btcminer021]

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..

I'm using the ASRock 970 Extreme4 in one of my rigs, and the most you can get without risers is 3 GPU's.

Yes, and the middle card runs HOT!

[Gazylion]

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

Add MSI FXA-GD65 - 6GPU (without any mods) and it's for like $100

[ssateneth]

MSI Z77A-G45 is confirmed to run 6 slots easily. I own 4 of them. I have 8 GPU's populated in two of them (2 dual gpu cards) BTW, yes, 7970s really DO use that much power. 3 reference 7970 at stock volts, underclock ram, and overclocked core 1100-1220mhz used 870 watts AC on my kill-a-watt. baseline hardware uses 25 watts. I now have 5 7970 on it and the rosewill lightning 1300 powering them stinks of melting wire insulation., likely in the area of 1450 watts AC.

[cptmooseinc]

Why are my GPUs pulling so much power then? I have 5 Powercolor AX7950s running on the Gigabyte UD-5 motherboards. 1 of them has 4 powered risers and 1 non-powered riser and it's pulling a total of 1240W. No powertune on it. Engine at 950 and Memclock at 1490. Seems like a lot. Only getting ~537kH/s per card. I was getting 582kH/s out of them on the same rig with +10 powertune, but it was drawing so much power that it tripped the power strip because it wanted more power than the PSU could provide!

[ssateneth]

Why are my GPUs pulling so much power then? I have 5 Powercolor AX7950s running on the Gigabyte UD-5 motherboards. 1 of them has 4 powered risers and 1 non-powered riser and it's pulling a total of 1240W. No powertune on it. Engine at 950 and Memclock at 1490. Seems like a lot. Only getting ~537kH/s per card. I was getting 582kH/s out of them on the same rig with +10 powertune, but it was drawing so much power that it tripped the power strip because it wanted more power than the PSU could provide!

It pulls a lot of power because it pulls a lot of power. No way around it aside from undervolting and lowering frequencies and getting less hashes. Use a stronger power supply and electrical circuit or less video cards if you want fast speeds. Your choice.

[boozer]

Add MSI FXA-GD65 - 6GPU (without any mods) and it's for like $100

Yea.... good choice, but I just really like the on-board power/reset buttons and on-board diag LED of the MSI 990FXA-GD80 V2.

Saves me from having to hook up speaker/power/reset switch on my wood-frame open-air rigs.  So saves me time and whatever cost of purchasing those items would be.... for $40 more.

Although I have yet to verify if it runs 6 cards... hopefully I will find that out tonight.

[ButchHashidy]

Anyone have pointers on stuffing one of the larger video cards in just one single slot rather then occupying two?  Water cooling?  Any tuts out there in the wild?

[matt_trade]

Hi everybody,

I'm getting ready to build a 6 GPU rig that I would like to upgrade to a 24 GPU rack.
The rack info can be found here: https://bitcointalk.org/index.php?topic=191117.0
Here is a picture:
http://www.awtti.com/images/LTCminingrig9.png

I don't have much time to test the 6 GPU setup itself as I will have plenty of work to do on the frame. So I'm looking for a proven 6 GPU set up that will fit 6 x 7950 or 6 x 7970.
I would like to use the latest available motherboard since the older ones slowly become discontinued.
So far, here are all the post I have found on this forum that talk about 6 GPU setups.
https://bitcointalk.org/index.php?topic=188334.0
https://bitcointalk.org/index.php?topic=169718.0
https://bitcointalk.org/index.php?topic=105615.0
https://bitcointalk.org/index.php?topic=186877.0
https://bitcointalk.org/index.php?topic=97154.20
https://bitcointalk.org/index.php?topic=142241.msg1515460#msg1515460
After reading them, I'm still not sure which Motherboard I should go with. My only restriction is the format: ATX

COOLING:
I'm planning to start with air, what the rack was originally designed for. Once it passes the test, I'm going to switch to Oil Cooling.
With the oil cooling, I will test 2 options:
1. Air cooling of the oil outside of the rack room via a large radiator and fan.
2. Water cooled heat exchanger using a cold water source (in my case, irrigation water since available).

I look forward to your feedback. Thank you Boozer, scifimike12 & ssateneth for your feedback!

[sveetsnelda]

For 6 GPUs, I prefer the Z77A-GD65.  No presence pins need shorted, there are power buttons on the MB, and there's a 2 digit POST debug readout.  Technically you could run 7 cards on this MB with the right processor (the bottom slot is only active when an Ivy Bridge CPU is installed).

I have 9 of these rigs running with six 7950s each.  No powered risers, 1040-1070mhz per card, and 300mhz ram clocks.  They're stable.



https://i.imgur.com/2feHArI.jpg

[boozer]

For 6 GPUs, I prefer the Z77A-GD65.  No presence pins need shorted, there are power buttons on the MB, and there's a 2 digit POST debug readout.  Technically you could run 7 cards on this MB with the right processor (the bottom slot is only active when an Ivy Bridge CPU is installed).

I have 9 of these rigs running with six 7950s each.  No powered risers, 1040-1070mhz per card, and 300mhz ram clocks.  They're stable.

Very nice man.... It has the 2 digit post LED on it?  I might have to rethink things .   No powered risers at all with 6 cards per board?  That would make me a bit nervous... how long they been running like that?

I assume at those RAM clocks its for SHA256 mining?  Have you tried Scrypt (LTC, etc)?  What hash rate do you get on average with them?

[boozer]

Also, as an FYI, i did get 6x7970 working on the MSI 990FXA-GD80 V2, but I had to Jumper A1 to b17 anywhere I used a 1x to 16x pci connector.   I also set pci latency to 96 from reading elsewhere but do not know if that has any effect or not.

[mercSuey]

For 6 GPUs, I prefer the Z77A-GD65.  No presence pins need shorted, there are power buttons on the MB, and there's a 2 digit POST debug readout.  Technically you could run 7 cards on this MB with the right processor (the bottom slot is only active when an Ivy Bridge CPU is installed).

I have 9 of these rigs running with six 7950s each.  No powered risers, 1040-1070mhz per card, and 300mhz ram clocks.  They're stable.



https://i.imgur.com/2feHArI.jpg

Could you give a quick explanation of your OS setup.  I'm researching 6 gpu rigs and there's a lot of misinformation about compatibility and Win7 vs. Ubuntu/Debian.  I'd really appreciate some info or links to help my homework/research before I commit the $$.

[bitminer1]

I would also like info on your 6 gpu setup.  I have ordered 2 MSI 990FXA-GD65 V2 hoping to populate 6gpus without to many issues. If this Mobo does not work looks like the MSI Z77A-GD65 is in my near future.

Can anyone confirm the version 2 board will work I see above the normal version works with no problems. But they didnt state enviroment.

Seeing yours looks stable you mind sharing.  Also what PSU you using?

[CartmanSPC]

Look into the MSI Z77A-G45. It may not have that 7th card CPU limitation. It does not have a power button on the MB though :/

The third PCIe slot is gen2 on the Z77A-G45 instead of gen3 link the Z77A-GD65 which is fine for mining.

No powered risers on the Z77A-GD65 huh? I wonder if the Z77A-G45 needs powered risers.

Does the need for powered risers have anything to do with scrypt vs SHA?

[jaywaka2713]

Look into the MSI Z77A-G45. It may not have that 7th card CPU limitation. It does not have a power button on the MB though :/

The third PCIe slot is gen2 on the Z77A-G45 instead of gen3 link the Z77A-GD65 which is fine for mining.

No powered risers on the Z77A-GD65 huh? I wonder if the Z77A-G45 needs powered risers.

Does the need for powered risers have anything to do with scrypt vs SHA?

The Z77A-G45 will only run 6 cards. The 4th PCIe x1 slot disables itself when the other three are active. You will also need x1 to x16 powered risers.

[cptmooseinc]

To run six cards on this board (at least for scrypt mining), wouldn't you need two PSUs connected to get past the 1600W max PSU size you can buy to feed them? Or just get all undervolted cards on there? Would powered risers be needed if you undervolt the cards or no?

[jaywaka2713]

To run six cards on this board (at least for scrypt mining), wouldn't you need two PSUs connected to get past the 1600W max PSU size you can buy to feed them? Or just get all undervolted cards on there? Would powered risers be needed if you undervolt the cards or no?

I would use powered risers regardless just for the sake of not frying the motherboard. It also ensures you are getting the max hashpower possible, while protecting peace of mind