My Graphics Card has a 8+6 Power Connector. Do I need to plug in 2 seperate Cables ?

[MachmirIndiehos]

Hey !

 

i have a corsair rm650x PSU. it comes with with Cables that have 8+8 Pins. Can i use one of those or do i need to plug in to cables into a graphics card that has 8+8(6) power connectors ?

 

im concerned about sufficient current..

 

greetings

Julian

[GER_T4IGA]

those 8 pin are 6+2 so the additional 2 are optional. 8+6 means two plugs, one 8 and one 6 pin.
You are fine.

[MachmirIndiehos]

thanks for the answer !

yeah i know those are 8 / 6+2... but can one of those cables supply enough current or do i need two of those 8 / 6+2 cables ?

 

 

[GER_T4IGA]

1 minute ago, MachmirIndiehos said:

thanks for the answer !

yeah i know those are 8 / 6+2... but can one of those cables supply enough current or do i need two of those 8 / 6+2 cables ?

 

 

that depends on the card. Specification says 150W per 8pin but they can probably savely do more if you have a good PSU however the GPu side of things might not be suited for only using one cable, load wise. That would be out of spec and something I wouldn't even try to do.

[MachmirIndiehos]

so the safest way to do this would be using two seperate pci power cables to supply a grafics card with 8+8 or 8+6 connectors ?

[Guest]

You will be fine with the single cable.

[done12many2]

2 hours ago, MachmirIndiehos said:

so the safest way to do this would be using two seperate pci power cables to supply a grafics card with 8+8 or 8+6 connectors ?

 

Yes, that is best practice.  You many never need the overhead, but that's the correct way to do it.  

[MachmirIndiehos]

well now im fully confused. 

 

im just going to use two seperate cables and ignore the addition adapters each cable has..

 

THANKS for all the help !

[Guest]

16 hours ago, done12many2 said:

 

Yes, that is best practice.  You many never need the overhead, but that's the correct way to do it.  

It is perfectly fine to use a single cable. How do you think he would connect an SLI setup with that psu if the GPU required 2 x pcie connectors ? 

[done12many2]

7 minutes ago, lee32uk said:

It is perfectly fine to use a single cable. How do you think he would connect an SLI setup with that psu if the GPU required 2 x pcie connectors ? 

 

I understand what is acceptable and what is optimal.  I was simply stating what is best practice.  Sure you can place the load on one cable, but that's not what was intended when the card manufacturer provided two separate connections on the card.  

 

Also, PSUs are now coming with 2 to 6 PCIe connections for use with up to 6 individual PCIe cables to support multiple GPUs with more than one connection.

 

To further demonstrate how you'd "connect an SLI setup with that psu if the GPU required 2 x pcie connectors ?", here's a photo of a modern PSU with plenty of "VGA" or PCIe support.

[Guest]

2 minutes ago, done12many2 said:

 

I understand what is acceptable and what is optimal.  I was simply stating what is best practice.  Sure you can place the load on one cable, but that's not what was intended when the card manufacturer provided two separate connections on the card.  

 

Also, PSUs are now coming with 2 to 6 PCIe connections for use with up to 6 individual PCIe cables to support multiple GPUs with more than one connection.   

The Corsair RMx has 2 pcie cables with 4 connectors in total. It is perfectly safe to run GTX 1070 SLI for example by using one cable per gpu. The unit is a single rail anyway so you are not going to overload anything. 

[done12many2]

8 minutes ago, lee32uk said:

The Corsair RMx has 2 pcie cables with 4 connectors in total. It is perfectly safe to run GTX 1070 SLI for example by using one cable per gpu. The unit is a single rail anyway so you are not going to overload anything. 

 

Once again, I think you're missing my point.  I agree that it's perfectly safe.  I never said it wasn't.  I simply stated that best practice it to use a separate cable per connection on a video card.  Nothing more was said. 

 

If a card manufacturer puts two separate connections on a card, they intended for each to have its own supply from the PSU.  Using one cable with a spliced end is no different than only using one connection on the video card, which he can do as well.  He might as well only hook up one 8 pin if he's only using one cable.  It's the same concept.

[Guest]

54 minutes ago, done12many2 said:

 

I understand what is acceptable and what is optimal.  I was simply stating what is best practice.  Sure you can place the load on one cable, but that's not what was intended when the card manufacturer provided two separate connections on the card.  

 

Also, PSUs are now coming with 2 to 6 PCIe connections for use with up to 6 individual PCIe cables to support multiple GPUs with more than one connection.

 

To further demonstrate how you'd "connect an SLI setup with that psu if the GPU required 2 x pcie connectors ?", here's a photo of a modern PSU with plenty of "VGA" or PCIe support.

That picture is not relevant in any way though is it ? The Corsair RMx 650W which is the psu the op owns doesn't have that many VGA connectors on the psu housing as you can see in the Corsair link below.

 

http://www.corsair.com/en-gb/rmx-series-rm650x-650-watt-80-plus-gold-certified-fully-modular-psu-uk

 

Not even sure why we are arguing about this to be honest. Both ways will work fine so it isn't an issue. I just prefer the single cable option as it looks neater.

 

[done12many2]

11 minutes ago, lee32uk said:

Not even sure why we are arguing about this to be honest. Both ways will work fine so it isn't an issue.

 

Agreed. 

 

I also misread your post about his PSU.  I though you were talking about PSUs in general.  Sorry about that.  

[Quaker]

21 hours ago, MachmirIndiehos said:

i have a corsair rm650x PSU. it comes with with Cables that have 8+8 Pins. Can i use one of those or do i need to plug in to cables into a graphics card that has 8+8(6) power connectors ?

If I read this right, your power supply has one cable that ends with two 8-pin connectors. This is perfectly fine if the wires used in the cable are large enough to handle the current - which you can safely assume they are. (my CX650m is the same way.)

The reason why the graphics card has two separate connectors (1 8-pin, 1 6-pin) is that the thickness and width of the traces available on the graphics card circuit board are not enough to handle the current through only one connector - or more realistically, it's cheaper to use multiple connectors than to increase the thickness and width of the traces (plus other considerations such as the size and placements of filtering components on the power traces).

[done12many2]

1 minute ago, Quaker said:

The reason why the graphics card has two separate connectors (1 8-pin, 1 6-pin) is that the thickness and width of the traces available on the graphics card circuit board are not enough to handle the current through only one connector - or more realistically, it's cheaper to use multiple connectors than to increase the thickness and width of the traces (plus other considerations such as the size and placements of filtering components on the power traces).

 

That's actually the first time I've heard this one.  

 

My understanding was that a 8-pin connection has a 150w rated load and a 6-pin has a 75w rated load.  If a GPU's total draw was more than what the PCIe slot and a single 8-pin was rated to supply, then manufactures add a 8 + 6 or 8 + 8  combination to so as to not exceed the rated capacity of a single cable.

[MachmirIndiehos]

Thank you ! 

Reading all this really helped !

[Quaker]

20 hours ago, done12many2 said:

My understanding was that a 8-pin connection has a 150w rated load and a 6-pin has a 75w rated load.  If a GPU's total draw was more than what the PCIe slot and a single 8-pin was rated to supply, then manufactures add a 8 + 6 or 8 + 8  combination to so as to not exceed the rated capacity of a single cable.

Actually, I may have mis-spoke. Not only does it depend upon the current capacity of the traces on the circuit board, but the connectors themselves have a power "rating", although, that power rating tends to be a "nominal" value that can be exceeded. Because of the way the connectors are made, there is a nominal safe power rating to allow for the average contact integrity to prevent hotspots and melting. So,  the size of the traces on the circuit board do, also, match the power rating of the connectors.

 

But, the important part is that these power ratings are dependant upon the connectors and traces on the graphics card, not on the cable from the power supply.  If the wire in the cable is large enough, it can easily feed two connectors.