3080 power cords

[Ksalmon]

Hello, so I recently just built a friends computer for him and I noticed that his 3080 had three 8 pin slots, since we only had 2 gpu power cables we ran both power cables to the gpu and then daisychained one of the two power cables into the third slot on the gpu, is this acceptable?

[Fasauceome]

9 minutes ago, Ksalmon said:

since we only had 2 gpu power cables we ran both power cables to the gpu and then daisychained one of the two power cables into the third slot on the gpu, is this acceptable?

Yes, one daisy chain plus one separate cable is just fine.

[BOBWARPATH]

8 minutes ago, Ksalmon said:

Hello, so I recently just built a friends computer for him and I noticed that his 3080 had three 8 pin slots, since we only had 2 gpu power cables we ran both power cables to the gpu and then daisychained one of the two power cables into the third slot on the gpu, is this acceptable?

I think most people in this situation would tell you to use 3 seperate power connectors, because the 3080 is such a power hungry card. It depends what you are playing. I know back in the day when me and the boys built a 660ti system, we ran a daisy chained power setup on it for the longest time and had no issue. What is the wattage of your psu? Thats a better question

[Motifator]

Which PSU are you running and what exactly kind of conversion did you guys do? You didn't use Molex for this, right?

[jones177]

It depends on what 3080 you have.

An 8 pin connector is rated at 150 watts. A PCIe slot is 75 watts. So 375 watts.

 

Some cards(Tuf) draw 340 watts, others(Strix) draw 370 watts and some 400 watts(FTW3).

 

I lost a card and a motherboard with a PCIe cable so I play it safe.

 

 

[Motifator]

1 minute ago, jones177 said:

It depends on what 3080 you have.

An 8 pin connector is rated at 150 watts. A PCIe slot is 75 watts. So 375 watts.

 

Some cards(Tuf) draw 340 watts, others(Strix) draw 370 watts and some 400 watts(FTW3).

 

I lost a card and a motherboard with a PCIe cable so I play it safe.

Those ratings are horse shit. The cable is well capable of pulling way more without even coming close to burning. They're very conversely rated. Old dual GPU cards were an example of this.

For instance my 1500i has the OCP at 40a on each cable aka 420W, you'd think Jonnyguru would know what he's doing, right? Otherwise he'd limit them to 150W.

[ewitte]

Copied real ratings from a post I did a few weeks ago

 

"here is the breakdown for the entire cable

20 gauge PCIE cables - maximum 150W

18 gauge PCIE cables - maximum 288W

16 gauge PCIE cables - maximum 444W

 

Both the 750W and 1000W PSU I have show 18 gauge for the single cables and "16-18" for the dual connector cables so they can handle somewhere between 288W and 444W each.'

[jones177]

5 minutes ago, Motifator said:

Those ratings are horse shit. The cable is well capable of pulling way more without even coming close to burning. They're very conversely rated. Old dual GPU cards were an example of this.

For instance my 1500i has the OCP at 40a on each cable aka 420W, you'd think Jonnyguru would know what he's doing, right? Otherwise he'd limit them to 150W.

Cables are not all the same. Some are junk.

I had an GTX 980 ti SLI rig. Each 980 ti draw 250 watts. I used one cable(8 pin plus 6 pin) for each 980 ti and lost one and the motherboard. 

Since then I go by those "horse shit" ratings.

 

 

 

[Motifator]

I realize that, but the melting point of the average mid - high to high end PSU cable is indeed around 400-450W in case an internal short happens / something goes south. 

You're ultimately causing an external issue by using adapters like in the OP's case, that's not the problem of the PSU itself but the method. Also, it really doesn't matter that the cable carries two plugs on it... unless you have a pot on the card and are pulling an enormous amount of power.

It's probably another factor such as the PSU itself being crap, or something else causing it. These cables can withstand intense overclocking sessions to no end realistically. The cables are almost never the reason, but something else is. You can have the PSU blown and cables burnt, then blame it on the cables when it was something entirely else.

[Tegneren]

9 minutes ago, Motifator said:

You're ultimately causing an external issue by using adapters like in the OP's case,

He didn't say he used an adapter, but the "piggyback" splitter from one of the cables, which would most likely be just fine. But it do depend on the PSU.

For a 3080 i wouldn't go any lower than 850W unless it has good protection against transient loads

[Motifator]

16 minutes ago, Tegneren said:

He didn't say he used an adapter, but the "piggyback" splitter from one of the cables, which would most likely be just fine. But it do depend on the PSU.

For a 3080 i wouldn't go any lower than 850W unless it has good protection against transient loads

In that case, they're just putting two plugs in one. Not much wrong with that because...



There's actually no additional power being delivered from the 2 extra pins on 8-pin, they're ground pins. You get the power from the 6-pins, the other two were originally created solely to prevent people from plugging HD 2900 XT's and 8800 GTX's to incapable PSUs.

[Mick Naughty]

I use 2 cables for my 3090. As my adapters only take 2 8 pins cables. And cant fully utilize the card anyway.

[jones177]

1 hour ago, Motifator said:

I realize that, but the melting point of the average mid - high to high end PSU cable is indeed around 400-450W in case an internal short happens / something goes south. 

You're ultimately causing an external issue by using adapters like in the OP's case, that's not the problem of the PSU itself but the method. Also, it really doesn't matter that the cable carries two plugs on it... unless you have a pot on the card and are pulling an enormous amount of power.

It's probably another factor such as the PSU itself being crap, or something else causing it. These cables can withstand intense overclocking sessions to no end realistically. The cables are almost never the reason, but something else is. You can have the PSU blown and cables burnt, then blame it on the cables when it was something entirely else.

The PSU was a Corsair 850 I bought in 2015. It was my first modular PSU.

The point of failure was at the connector, on the side facing the GPU.  I only noticed it after unplugging the GPU.

I replaced all the cables with a sleeved kit. 

 

I do not have a lot of faith with the cables that come with PSUs.

Since 2019 I have had 2 cable failures out of 7 builds.

One was the 24 pin on an EVGA 1300 G2. The other was a PCIe cable on a 1000 watt EVGA G+.

It took over 6 months for the issues to come up and I consider the cause to be poor quality control.

 

I also have setups that use more than 150 watts on an 8 pin but there is nothing budget about them.

One of my 3090 tis has a 12 pin to 2x 8 pins(2 pins blank) cable with the instructions to use it with a 1000 watt PSU. 

It is beautifully made and I can trust it to do the job.

 

[PowerLife]

First I want to say there is a reason certain cards list 3 X 8 Pin power cords while others from the same manufacturer will say 2 X 8 Pin and so on. Its been years since the release and we know what these cards and do and depending on the card it's a 320-340 Watt card. 

 

Thicker gauge wiring and going from 2 plugs to 3 plugs will help reduce heat and provide better power. I don't see a reason to daisy chain anything but fans IMHO. 

[ewitte]

On 7/22/2022 at 1:06 AM, PowerLife said:

First I want to say there is a reason certain cards list 3 X 8 Pin power cords while others from the same manufacturer will say 2 X 8 Pin and so on. Its been years since the release and we know what these cards and do and depending on the card it's a 320-340 Watt card. 

 

Thicker gauge wiring and going from 2 plugs to 3 plugs will help reduce heat and provide better power. I don't see a reason to daisy chain anything but fans IMHO. 

Some brands give enough connectors and cables to do so, some do not.  For instance they may support 4x8pin but only have two jacks on the back of the PSU.