pcie 8pin explained?

[Guest]

So we all know that 8pin has 2 more pins that 6 pin. 6pin is split on 3 12V and 3 grounds. Power rating of 6pin is around 75W and 8pin 150W. But problem I have is that only things added on 8pin are two more grounds, not one 12V and one ground. 

So my question is how can two more grounds even have an impact on power rating? 

 

only thing how I explain this is that by standard 8pin must have thicker wires.

 

 

 

EDIT: So 8 pin does not add two more grounds only as I previously thought. Images that are marked as solved describe what are differences in connectors.

[QueenDemetria]

only thing how I explain this is that by standard 8pin must have thicker wires.

Pretty much

[W-L]

So we all know that 8pin has 2 more pins that 6 pin. 6pin is split on 3 12V and 3 grounds. Power rating of 6pin is around 75W and 8pin 150W. But problem I have is that only things added on 8pin are two more grounds, not one 12V and one ground. 

So my question is how can two more grounds even have an impact on power rating? 

 

only thing how I explain this is that by standard 8pin must have thicker wires.

 

It has to do with the number of amps that can be put through the ground wires more ground wires means more possible amps to be supplied to the card, so more power.

[Glenwing]

More grounds allows more current through the 12V lines.

[Guest]

It has to do with the number of amps that can be put through the ground wires more ground wires means more possible amps to be supplied to the card, so more power.

yea so you take one 1mm thick 12V wire and 10cm thick ground and it will be able to give it power based on ground? It does not work like that.

[Guest]

More grounds allows more current through the 12V lines.

But if 12V lines dont allow enough you can have 100 grounds 12V ones would "bottleneck"

problem is why it has uneven number of 12V and grounds?

[W-L]

yea so you take one 1mm thick 12V wire and 10cm thick ground and it will be able to give it power based on ground? It does not work like that.

 

Not like that exactly it somewhat also has to do with the design of how they delivery power also since the 6 and 8 pins on a PCI-E are not all ground or 12V power wires are used for power delivery some are used as a sensor wire, or not used at all.

 

8 pin:

12V - 3 wires

GRD - 3 wires

 

6 pin

12V - 2 wires

GRD - 2 wires

[Guest]

-snip-

Oh these pictures are changing lot of things. I didn't knew there were some others uses on some of cables (those sense). Thanks

[W-L]

Oh these pictures are changing lot of things. I didn't knew there were some others uses on some of cables (those sense). Thanks

 

I'll be honest though if you switch those ground wires around they still work which was an odd thing when I first read about it since I re-pinned my PSU when sleeving and it works no problem. They apparently just look for the ground to be there to know there is a connector plugged in and the difference between an 8 and 6 pin since a while ago some cards let you plug in a 6 pin power into a 8 pin plug.

[Guest]

I'll be honest though if you switch those ground wires around they still work which was an odd thing when I first read about it since I re-pinned my PSU when sleeving and it works no problem. They apparently just look for the ground to be there to know there is a connector plugged in and the difference between an 8 and 6 pin since a while ago some cards let you plug in a 6 pin power into a 8 pin plug.

That should not be a problem. All 12V cables are in psu connected in same spot. Same is with gnd. 

Do you mean that you switched sense with gnd?

[W-L]

That should not be a problem. All 12V cables are in psu connected in same spot. Same is with gnd. 

Do you mean that you switched sense with gnd?

 

The sense cables are also ground cables as far as the PSU is concerned but the GPU is the thing that considers it a sense cable since it detects what type of connector is plugged in and yeah they criss-crossed horribly on my PSU  with no pattern between multiple sets of cables so I just remapped it all.

[Guest]

The sense cables are also ground cables as far as the PSU is concerned but the GPU is the thing that considers it a sense cable since it detects what type of connector is plugged in and yeah they criss-crossed horribly on my PSU  with no pattern between multiple sets of cables so I just remapped it all.

yea I have idea about how that works.

It came like that out of box or what?

[W-L]

yea I have idea about how that works.

It came like that out of box or what?

 

Yeah once I took off the original black sleeve and started separating them for individual sleeving they needed some sorting out before continuing, since on the PSU end the pattern would get all mixed up.