Bitcoin Forum

Hi

So basically I've got a cm750x corsair power supply and it doesn't have that many apots for gpus.
Only 3 and one goes for the cpu so two remain.

The thing is these cables are 6+2 pin connectors and at the end there's branching to give another 6+2 pins.

It's like what's in the image below:

http://d2ydh70d4b5xgv.cloudfront.net/images/0/d/evga-pcie-8-pin-to-dual-6-2-pin-pcie-graphics-card-gpu-power-cable-31-original-86a186a19076b18c1cd17166e4277507.jpg

The question is can two gpus be used on ghe same cable ?

And anither question is what is the maximum nuber of cards to work stable on a 750 watt psu ?

Ty in advance

You need to calculate the power output. It should not exceed 150+75 = 225W in total.

In my experience one cable straight from power to gpu is better but not necessary , and your PSU can run 2-4 gpus with good efficiency with a little downvolt.

I ran 1x7950 1xr9 380x 1x rx480 on 675 watt before but you need to down the powerlimit a decent amount to get stable mining experience.

This answers to your questions largely depend on what kind of cards you have. In most cases, you should be fine with two GPUs on the same cable. However, I'd avoid using two cards that both require the full 8 pin PCIe connector. You might be okay, but you might not, and I'd err on the side of caution. In general, two cards that only need 6 pin connectors should be fine using the same branch. One 8 pin and one 6 pin should also be fine (in general). As Benarand mentioned, you'll need to check out the max power draw of each of your cards and estimate the max power draw you'd expect to be drawn through the PCIe power connectors or the slot/riser for your specific cards.

Monitor your rig for a good 30+ minutes after you have all the connections sorted out and start mining. Try to feel if the wires and/or connectors are significantly hotter than the surrounding air. That's a sign that you might not want to run them 24/7 in that configuration. (However, the inverse isn't necessarily true: Just because you can't feel them running hot does not mean that there's no problem.)

For your second question, you'll need to estimate your total power draw based on your specific hardware. Generally, you want your estimated total power draw to be less than about 70% of your power supply's rating. Many are fine when pushed closer to the rating, but err on the side of caution, since most consumer power supplies weren't intended for 24/7 operation. (And blowing a power supply is no fun.) Corsair usually sells quality PSUs, even their budget ones are pretty good, although any PSU from any brand can turn out to be a dud.

Yes you can run 2 GPUs with that split-end cable. However...

Make sure you put GPUs close enough so the length is long enough

After a few hours touch the end of the cable going into the modular PSU and make sure its not burning hot. Sometimes there is a bad connection and they will melt.

All of your questions depend upon what cards you have.


As a rule of thumb, nvidia cards use less power than AMD cards. What cards exactly are you using with this rig?

You'll also want to find out the power usage of your entire system. I use pcpartpicker for this. Most mobo+CPU+ram combos come out between 110W-150W... some CPUs use a lot more though.

Ok I just got the new gpu and connected them that way.
I'll keep an eye on that cable as you said and hopefully it won't burn or something *fingers crossed*



Oh they're nvidia cards. To be specific they're gtx 1060s. And I just got to that site and in theory I can use 4 gpus but it's kinda risky.

The system without any gpus uses about 140w. And each card about 120w.

So (120*4 ) + 140= 620w.

And it should be able to handle 750w right ?
But I was told that I shouldn't try to push the PSU to the limit. So I'll buy another 750 or 850 one to be safe.

Yes, if they are 1060's with a single 6 pin connector, you can run 2 cards off one cable. I'm running an 8 x 1060 rig and I do 2 cards per power connector.

I also run the 1060's at 80% power since there is very little increase in performance above that so they're pulling under 100w each. I run 4 x 1060's, the motherboard, cpu, ssd, etc on an 850w, and the other 4 cards on a 750w. I thought I could do 2 x 750w but I had instabilities setting up the whole system when the cards are pulling the full power. When the power draw is decreased, people say 2 x 750w should be fine but the system is rock solid with an 850/750 combo.

Gtx 1060 cards don't use alot of power, so you're most probably ok using these cables, i had a thermaltake psu with a cable like this and i was using it on a gtx 1080 and an rx 580 and it was running fine.

Hi I have exactly such a configuration running since quite a time with 2 1060.. it's running just fine.
In the end this doesn't mean much but its a clear sign  :)

One is an msi which uses 8 pins and the other is asus (dual oc) which uses 6 pins. And a separate 8 pin asus (strix). Should be fine right ?


Ok then. When I add more cards I'll get an 850w one to make it stable.  :)


Thanks a lot mate. You just gave me a relief.
I'm the kinda guy who is too afraid that anything blows or something  ::)

Yes, that should be ok, my 750w PSU is now running a gtx 1080, rx 580 and gtx 1060, at one time it was running 2 rx 470s, the 1060 and the 580, all was going smooth, as long as you're not over loading on your cards to use like 200w you're ok, i think the max tdp for a gtx 1060 is not even 140w

Everything has been working fine for a week now.
Two gpus plugged one 6-pin and the other 8-pin.

I'm locking this thread as I guess there's nothing new that's gonna be added.

Thanks everybody who replied.