Splitting the PCI 6PIN/Molex power lines?

[Bolchevickos]

Hi,

I have the project to build a second mining rig. For this one I would like to use 12 RX560 with 2 GB of memory.
I was hoping to find some help and answers to a few questions I have.

For the motherboard I was planning to use the Asrock H110 Pro BTC+, I think there shouldn't be much issues to get the GPU work in Linux.
The main concern I am facing at the moment is how to power the thing. @40W/gpu, 800-1200W would be largely sufficient. I was thinking about connecting 2*600W PSU.
The problem will still be to get enough PCI 6 PIN power lines. I do not know any power supply in this range providing more than 2-3 lines. I saw there was some splitters, do you think that could do the trick? Even If I split one line into 4 others, the power draw would still be quite low into theory (<200W)? Would that work?

Similarly, would you see any issue with splitting the MOLEX?
I am very open to any other suggestions you may have.

Many thanks for your inputs,

Bolchevickos.

[Undefined31415]

Hi,

I have the project to build a second mining rig. For this one I would like to use 12 RX560 with 2 GB of memory.
I was hoping to find some help and answers to a few questions I have.

For the motherboard I was planning to use the Asrock H110 Pro BTC+, I think there shouldn't be much issues to get the GPU work in Linux.
The main concern I am facing at the moment is how to power the thing. @40W/gpu, 800-1200W would be largely sufficient. I was thinking about connecting 2*600W PSU.
The problem will still be to get enough PCI 6 PIN power lines. I do not know any power supply in this range providing more than 2-3 lines. I saw there was some splitters, do you think that could do the trick? Even If I split one line into 4 others, the power draw would still be quite low into theory (<200W)? Would that work?

Similarly, would you see any issue with splitting the MOLEX?
I am very open to any other suggestions you may have.

Many thanks for your inputs,

Bolchevickos.

Do the RX560s really only draw around 40W/card? I was under the impression that it was closer to 70-75W.

Anyhow, if all of your cards are use 6-pin connectors, you would probably be fine using an 8-pin PCIe to 2x 6-pin adapter with the 6+2 connectors on the PSU(s) you buy. Most PSUs have either one or both of the PCIe power connectors as a 6+2 pin connector, making the cable have either 2x 6+2 or 1x 6+2 and 1x 6 pin. Combining either of those configurations with one splitter lets you connect power to 3 RX560s.

The PSU cable should definitely be able to handle the load of 3x RX560s, since it should've been made to handle powering 1x 8-pin and 1x 6-pin (or even better, 2x 8-pin) connections simultaneously.

This is an example of a splitter that would do the job (note: I am not necessarily recommending this specific adapter. Do your own research and get a high-quality adapter with good cabling):
http://www.ebay.com/itm/PCI-e-8pin-to-Dual-8Pin-PCIe-8pin-2x-6-2pin-Graphics-Video-Card-Power-Cable-R-/172783728372
I would strongly suggest that you avoid using something like this as a 1x 8-pin to 2x 8-pin splitter, however. That might be pushing it. For this purpose, you'll only need to use it as a 1x 8pin to 2x 6-pin adapter.

Question: What risers are you planning on getting? 6-pin powered ones? 4-pin molex? SATA?

[Bolchevickos]

Thank you very much for your input.
I have bought 2 for my tests, they do draw 40W (slightly less if you really target a low consumption) at the wall, modded, underclocked...
Regarding the riser, I am not sure at the moment. I think I will do molex like the ones I am using on my current rig. The problem is that it will raise the same issue. No PSU has 6 molex...so might try a combo of molex and sata..

[Undefined31415]

Thank you very much for your input.
I have bought 2 for my tests, they do draw 40W (slightly less if you really target a low consumption) at the wall, modded, underclocked...
Regarding the riser, I am not sure at the moment. I think I will do molex like the ones I am using on my current rig. The problem is that it will raise the same issue. No PSU has 6 molex...so might try a combo of molex and sata..

Most modular EVGA PSUs will allow you to swap out the SATA lines for 4-pin molex ones. All you need to do is get in touch with EVGA support and see if they'll send you some extra molex cables. (Mixed results with getting these free, usually better luck after purchasing higher-end units. They might tell you to buy their bulk modular PSU cable pack, which isn't a good deal if you only need the molex cables.)

Modular PSUs from other brands will probably give you options for more than 6 4-pin molex connectors. (Never mix cables between modular PSUs unless you verified that they are compatible.)

[chtat12]

EVGA quoted me $5.99 for each molex cable (1300W G2) + $15 S/H. For some reason it turned into ~$33 ish for 4 cables by the time I got an invoice.

[bouldou]

Hello, I'm just curious : what will you mine with those cards ?

Thanks 

[fanatic26]

You really should think about getting the 4gb variants, you are limiting what you can mine with those 2gb cards

[Bolchevickos]

Hello guys, many thanks for all these answers. I have identified an interesting psu with 2 pci 8 pin that I will split + 2 molex that I will turn into 6PIN. This should work.
Regarding what I intend to mine, I will go for xmr for which the 2gb wont make much a difference.

[Undefined31415]

Hello guys, many thanks for all these answers. I have identified an interesting psu with 2 pci 8 pin that I will split + 2 molex that I will turn into 6PIN. This should work.
Regarding what I intend to mine, I will go for xmr for which the 2gb wont make much a difference.

I'm hoping that your "interesting psu" is from a reputable brand. (While any PSU can be a dud, those with the guts manufactured by Seasonic, Super Flower, and FSP come to mind as being higher quality.)