6 Graphics Cards Power Issue, Complex Problem

[ImInjured]

I purchased 6 GTX 1070s for a mining rig. 5 of them are EVGA FTW and the last is an ASUS Strix.

The ASUS Strix requires 1 8pin power connector.

The EVGA FTW's however require 2 8 pin power connectors.

 

This is a major problem because I need to connect them all to one single 1200w power supply which only has 6 VGA power cables.

 

Each EVGA FTW came with two 6pin to one 8 pin adapters and I have 3 power cables with both an 8 pin and 6 pin cable. But even if I had 6 of these I could only power 9 slots and I need to power 11. I was doing testing and managed to get a single card to work with just one 8pin + 6 pin cable by plugging in the 8 pin, and using the 6 pin to 8 pin adapter with only one of the 6 pin slots filled. I tried to duplicate this with two cards but no luck.

 

If I were to get a single 6 pin to 8 pin adapter would this work so that I could use a 6pin + 8pin power cable to power both 8pin slots or could this cause issues?

Is there a way to make the card work with only filling one 8 pin slot?

 

TL:DR; I need to power 2 8-pin connectors on my graphics card using 1 PSU slot.

[vanished]

I would not advise splitting a 6 pin (designed for 75 W) to an 8 pin (designed for 150 W).  Sure the connectors can physically withstand more than that but those are the specs and so the PSU would not likely have been built to be able to provide anything more than that.

[ImInjured]

1 minute ago, Ryan_Vickers said:

I would not advise splitting a 6 pin (designed for 75 W) to an 8 pin (designed for 150 W).  Sure the connectors can physically withstand more than that but those are the specs and so the PSU would not likely have been built to be able to provide anything more than that.

Ah gotcha. Seems like the only solution might be to get another power supply or different graphics cards. I guess what I'm asking is is it possible to power 6 graphics cards with 11 total 8 pin slots with only 6 8 pin connectors coming from the power supply.

[ImInjured]

Even simpler put, I need 1 PSU cable to power 2 8 pin connectors.

[8uhbbhu8]

Why not just grab another psu specifically for the gpus?

[Lord Nicoll]

6 GTX 1070's, based sole off of TDP, which is not power usage but tied closely too it, states 150 watts, given reference has only an 8 pin, if you set the GPUs power target to about 80%, they should do pretty fine even with loads of adaptors, but 1200 watts isn't really enough for that many GPU's, and make sure your PCIe power from the slot is supplemented if the cards draw any power from it. 

[ImInjured]

17 minutes ago, 8uhbbhu8 said:

Why not just grab another psu specifically for the gpus?

 

5 minutes ago, Lord Nicoll said:

6 GTX 1070's, based sole off of TDP, which is not power usage but tied closely too it, states 150 watts, given reference has only an 8 pin, if you set the GPUs power target to about 80%, they should do pretty fine even with loads of adaptors, but 1200 watts isn't really enough for that many GPU's, and make sure your PCIe power from the slot is supplemented if the cards draw any power from it. 

Yeah looks like I'll be grabbing another PSU for 3 of the cards and I'll use the current for 3 cards. Only problem is my case doesn't fit 2 power supplies so I think I'll have to mount it on the top or side of the case. Oh well this is supposed to be a mining rig, not look great

 

Thanks for the replies. Just had to make sure this was my only option before dropping the cash.

[Lord Nicoll]

3 minutes ago, ImInjured said:

 

Yeah looks like I'll be grabbing another PSU for 3 of the cards and I'll use the current for 3 cards. Only problem is my case doesn't fit 2 power supplies so I think I'll have to mount it on the top or side of the case. Oh well this is supposed to be a mining rig, not look great

 

Thanks for the replies. Just had to make sure this was my only option before dropping the cash.

I would actually recommend a rack mount type solution is you want it to at least be all in the same box, 4U chassis should be able to house 2 full size ATX units, or 4 server type units, and server PSUs are usually pretty awesome, but a custom case for a mining rig is not something that scales well however I'd be surprised if no one else is selling GPU oriented rack mount cases for miners,

[ImInjured]

37 minutes ago, Lord Nicoll said:

I would actually recommend a rack mount type solution is you want it to at least be all in the same box, 4U chassis should be able to house 2 full size ATX units, or 4 server type units, and server PSUs are usually pretty awesome, but a custom case for a mining rig is not something that scales well however I'd be surprised if no one else is selling GPU oriented rack mount cases for miners,

Yeah I'm using a 4U server case. 

 

Here's a picture:

[scottyseng]

5 minutes ago, rrubberr said:

Supermicro Superservers (what I use for GPU compute) max out at 4 dual slot cards.

They do make one with ten card support (if you use the two PCIe 2.0 x 16 slots in the center, but yeah, you need dual Xeons for it...it's that one server Linus showed off in the 10 gamers one PC thing...

 

@ImInjured Yeah, I have to agree with the above, the power draw will be too high for all of those for 1200W (at least from what I remember).

[Lord Nicoll]

12 minutes ago, ImInjured said:

snip

Oh that's kinda narly, I can think of 3 or 4 better ways to lay that out but it'd cost more, although probably work out better, but definitely hurt the margins.

[ImInjured]

4 hours ago, Lord Nicoll said:

Oh that's kinda narly, I can think of 3 or 4 better ways to lay that out but it'd cost more, although probably work out better, but definitely hurt the margins.

It was a relatively easy build, I liked the space. I have a fan rack going in the middle.

 

Know of any power supplies with 6 VGA slots that wont break the bank?

[ImInjured]

4 hours ago, rrubberr said:

http://www.guru3d.com/articles_pages/nvidia_geforce_gtx_1070_review,8.html

 

About 161 watts apiece under full load.

Yeah I thought I was pushing it anyway but was hoping I could tune them down enough to make it work.

[Lord Nicoll]

1 hour ago, ImInjured said:

It was a relatively easy build, I liked the space. I have a fan rack going in the middle.

 

Know of any power supplies with 6 VGA slots that wont break the bank?

Other than a 2nd hand AX1500i, not really, 6 8+8 pins is something I've only seen on the 1500 and 1600 watt units, Sorry about that.