# Regarding 6-pin PCIe rated wattage!



## GordonFreemanInTheFlesh (Jul 31, 2022)

When 6-pin PCIe first came out it was rated for *75w(20-22 AWG) *but the difference of 6-pin to 8-pin is very similar in fact I see no reason why a 6 pin cannot provide *150w*.
The connectors both 6/8-pin have only *3x12v* lines, with the 8-pin having an extra ground and sense wire that provide "Stability".
I am fairly confident that by upgrading the wire gauge from *(20 to 16/14 AWG)* the use of a 6-pin to 8-pin cable should not be an issue!

_Edit: Theoretically a (16awg) 6-pin PCIe cable can deliver 360w, each 12v line supplying 120w_.


*Thank you for your time!*


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## eidairaman1 (Jul 31, 2022)

Arbër said:


> When 6-pin PCIe first came out it was rated for *75w(20-22 AWG) *but the difference of 6-pin to 8-pin is very similar in fact I see no reason why a 6 pin cannot provide *150w*.
> The connectors both 6/8-pin have only *3x12v* lines, with the 8-pin having an extra ground and sense wire that provide "Stability".
> I am fairly confident that by upgrading the wire gauge from *(20 to 16/14 AWG)* the use of a 6-pin to 8-pin cable should not be an issue!
> 
> ...


It's not just the wire gauge but how the power supply outputs that current over those wires. Just because you increase the gauge doesn't mean the psu will put out more current, it has to be "programmed" in to do it.

Output from the pcie slot is still 75 Watts.

75W/12V=6.25A, so the rest has to come from the pcie cables.

So combined say gpu is 400 Watts, 75W comes from the PCIE slot, so that leaves 325W to come from two 8 Pin plugs, 325/2= 162.5W each

Pcie= 75W/12V=6.25A
8 Pin 1 162.5/12V= 13.542A
8 Pin 2 162.5/12V= 13.542A

Since there are three 12V Pins in a 8 Pin PCIE Plug they have to each handle 54.17 Watts/12V=4.51412A

That leaves 5 grounds

So 3 pins are Hot, 3 are Loop Ground, and 2 are a Chassis ground (ESD/Protection)


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## Mussels (Jul 31, 2022)

Arbër said:


> When 6-pin PCIe first came out it was rated for *75w(20-22 AWG) *but the difference of 6-pin to 8-pin is very similar in fact I see no reason why a 6 pin cannot provide *150w*.
> The connectors both 6/8-pin have only *3x12v* lines, with the 8-pin having an extra ground and sense wire that provide "Stability".
> I am fairly confident that by upgrading the wire gauge from *(20 to 16/14 AWG)* the use of a 6-pin to 8-pin cable should not be an issue!
> 
> ...


They added more ground wires to stop them melting, or sending that power through the GPU to ground out of the slot.


I've melted PCI-E cables before, it's not very fun.


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## eidairaman1 (Jul 31, 2022)

33.33 Amps is needed for that 400W GPU









						How Many Amps Does It Take to Kill You?
					

It takes between 0.1 and 0.2 amps to kill a human being. Shocks above 0.2 amps are not considered to be lethal because a human can be revived from that voltage if the victim receives immediate medical attention.




					www.reference.com
				




And all it takes is 0.15 amps or greater to take a person out.

Fyi 526VDC feels exactly like 120VAC (touched wires attached to a Megger while in operation doh!)


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## OkieDan (Jul 31, 2022)

eidairaman1 said:


> 33.33 Amps is needed for that 400W GPU
> 
> 
> 
> ...


Fortunately you have to have high voltage to overcome skin resistance to get much amperage flowing.


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## GordonFreemanInTheFlesh (Oct 5, 2022)

eidairaman1 said:


> It's not just the wire gauge but how the power supply outputs that current over those wires. Just because you increase the gauge doesn't mean the psu will put out more current, it has to be "programmed" in to do it.
> 
> Output from the pcie slot is still 75 Watts.
> 
> ...


I know this is kinda old but I couldn't help but notice your mistake in the begining there 

(QUOTE)
 "_Just because you increase the gauge doesn't mean the psu will put out more current, it has to be "programmed" in to do it_."

The reason you upgrade the wires to in this case 16/14awg is to prevent those wires from melting and also the PSU is not programed to send a certain amount of power through a particular line (connector)!
If the conditions are right (the conductors will handle such wattage without damage) the PSU will send that current until it dies!!
There is no PSU programming involved, the connected component will pull the watts it needs and if the PSU won't be able to deliver the power the PSU will likely shut down to prevent damage or in cheaper units let out the magic smoke!


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## 80251 (Oct 5, 2022)

I'd imagine the lumped lower resistance of lower gauge wires would allow for more current flow with less voltage loss.

HWiNFO64 reports my 1080ti can pull up to 471 Watts at 1.2V Vcore and 2164 Mhz. core clock, it also reports the voltage at both 8-pin PCIe connectors drops as far as 11.536V while the +12V slot voltage remains nearly constant.


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## GordonFreemanInTheFlesh (Nov 3, 2022)

80251 said:


> I'd imagine the lumped lower resistance of lower gauge wires would allow for more current flow with less voltage loss.
> 
> HWiNFO64 reports my 1080ti can pull up to 471 Watts at 1.2V Vcore and 2164 Mhz. core clock, it also reports the voltage at both 8-pin PCIe connectors drops as far as 11.536V while the +12V slot voltage remains nearly constant.


How many 8pin connectors does your 1080ti have?


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## 80251 (Nov 3, 2022)

@Arbër 
Two 8-pins.


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## GordonFreemanInTheFlesh (Nov 5, 2022)

80251 said:


> @Arbër
> Two 8-pins.


Thank you for the reply!


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## delshay (Nov 5, 2022)

Mussels said:


> They added more ground wires to stop them melting, or sending that power through the GPU to ground out of the slot.
> 
> 
> I've melted PCI-E cables before, it's not very fun.



GPUS also get ground from the chassis when you screw it down via the bracket.


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## 80251 (Nov 5, 2022)

There are also grounding slots in the PCIe slot connector.

For my 1080ti it's interesting that while the PCIe +12V 8-pins show voltage drops under load the +12V PCIe slot voltage never varies.


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## db87 (Nov 5, 2022)

See here for the analysis. In the optimal senario 360Watts are possible but the guidelines are from 2004 and at that time inferior materials and wires were much more common.
If you have a modern AAA-quality PSU, that 75Watt rating for the 6-pin PCIe is very very conservative.


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## Mussels (Nov 6, 2022)

delshay said:


> GPUS also get ground from the chassis when you screw it down via the bracket.


Yknow, NZXT's risers used non conductive screws as part of their fix for the "oops you're on fire" PCI-E risers


I wonder if we could find grounding issues with the GPU's mounting in the problem setups?



80251 said:


> There are also grounding slots in the PCIe slot connector.
> 
> For my 1080ti it's interesting that while the PCIe +12V 8-pins show voltage drops under load the +12V PCIe slot voltage never varies.


You likely have a multi rail PSU, and of course it works that way - the PCI-E slot has a lot lower load


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## 80251 (Nov 6, 2022)

@Mussels
No I don't have a multi-rail PSU (it's a Rosewill Capstone 750W Gold PSU) according to the johnnyguru review I read. I'm guessing the PCB doesn't route the +12V power from the PCIe slot to the same circuitry components as the +12V 8-pin PCIe power connectors. My guess is that so much +12V current is being sourced across the PCIe supplementary power connectors the resistance of the cables themselves comes into play.


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## Mussels (Nov 6, 2022)

80251 said:


> @Mussels
> No I don't have a multi-rail PSU (it's a Rosewill Capstone 750W Gold PSU) according to the johnnyguru review I read. I'm guessing the PCB doesn't route the +12V power from the PCIe slot to the same circuitry components as the +12V 8-pin PCIe power connectors. My guess is that so much +12V current is being sourced across the PCIe supplementary power connectors the resistance of the cables themselves comes into play.


If it's truly single rail, then you're losing voltage from resistance along the way - extensions, connectors, adaptors, loose connections, or just downright shitty measurements. You never know where they placed them in the circuit and as load increases voltages always drop.


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## GordonFreemanInTheFlesh (Nov 6, 2022)

delshay said:


> GPUS also get ground from the chassis when you screw it down via the bracket.


In PC world we refer to the Negative - as "Ground"
The chasis is connected to "Earth" ground which if this would happen .....  ground negative touch ground earth =House fire.


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## Mussels (Nov 7, 2022)

Arbër said:


> In PC world we refer to the Negative - as "Ground"
> The chasis is connected to "Earth" ground which if this would happen .....  ground negative touch ground earth =House fire.


That's different between countries, I believe

Like how many US sockets dont have a ground pin


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## GordonFreemanInTheFlesh (Nov 10, 2022)

Mussels said:


> That's different between countries, I believe
> 
> Like how many US sockets dont have a ground pin


They actually do have a ground female insert although it is very primitive, I wish the entire world used the british wiring system where each plug must have its own fuse! (I live in Kosovo but am very familiar with american wiring)
Where are you from?


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## 80-watt Hamster (Nov 10, 2022)

Mussels said:


> That's different between countries, I believe
> 
> Like how many US sockets dont have a ground pin





Arbër said:


> They actually do have a ground female insert although it is very primitive, I wish the entire world used the british wiring system where each plug must have its own fuse! (I live in Kosovo but am very familiar with american wiring)
> Where are you from?



Earth ground on all sockets has been code in the US since ... the '60s?  But many houses built before then (like my old AND current house!) have at least a few ground terminals that are simply not connected, because it's easy to drop in a 3-terminal outlet, but a PITA to run ground wires everywhere.


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## R-T-B (Nov 10, 2022)

Mussels said:


> Like how many US sockets dont have a ground pin


New ones must.  But old ones are not uncommon yeah.  Have a house from before the 70s and you may find a few.


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## OkieDan (Nov 11, 2022)

I almost had a home sale fall through because buyer didn't like the fact there were no grounds in the kitchen above the counters even though the house was built in '78.  I added GFCI outlets and pointed out that very few kitchen appliances have grounds plugs for it to matter.  I'd much rather have GFCI with no ground near water than ground without GFCI anyhow as a grounded device isn't going to trip a circuit breaker if it falls into water whereas pretty much any device will trip a GFCI if it's not waterproof.


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## Mussels (Nov 11, 2022)

You all kinda backed up my point with the whole
yes/no/maybe/heres alternatives

The USA has more home wiring options than two countries with different standards


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## 80-watt Hamster (Nov 11, 2022)

OkieDan said:


> I almost had a home sale fall through because buyer didn't like the fact there were no grounds in the kitchen above the counters even though the house was built in '78.  I added GFCI outlets and pointed out that very few kitchen appliances have grounds plugs for it to matter.  I'd much rather have GFCI with no ground near water than ground without GFCI anyhow as a grounded device isn't going to trip a circuit breaker if it falls into water whereas pretty much any device will trip a GFCI if it's not waterproof.



How does Ground Fault Circuit Interrupt work with no ground to fault?


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## OkieDan (Nov 11, 2022)

80-watt Hamster said:


> How does Ground Fault Circuit Interrupt work with no ground to fault?


Watch 3:59 to 4:33









I'm not an electrician.  I guess it senses hot is going to ground somehow, I don't know how.

Edit: I believe that the GFCI detects that there's slightly more current running through one conductor than the other and that's what causes it to trip.  When you have a working device drawing power from the outlet it should cause the same amount of current to flow through neutral and hot sides when in operation so it doesn't trip the GFCI.  Now if your device fell into water it would trip the GFCI if there is a path to ground as the hot wire would have more current flowing than neutral.


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## delshay (Nov 11, 2022)

Arbër said:


> In PC world we refer to the Negative - as "Ground"
> The chasis is connected to "Earth" ground which if this would happen .....  ground negative touch ground earth =House fire.



Have you put a multimeter to the PC PSU mains input "Earth wire" & the output of the PSU "ground wire"?

If you have then it would read 0 ohms regardless if you select continuity test or ohms test. It reads 0 ohms. In other words, the mains input "Earth wire" & the output ground wire are tied together. 

This means your statement of house fire is incorrect, false.


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## delshay (Nov 11, 2022)

Arbër said:


> Dude the Ground in DC is *The Negative(-) lead!.....If you were to short (Ground negative-) To mains earth your'd trip the breaker!*
> _Something tells me you don't know much about electricity (I'm an eletrician by profession btw !).
> 
> 
> No hard feelings fam.  I have another thread about cooling fans you can help me with ._



If there was a potential difference between the two I would believe you, but it reads zero ohms with a multimeter.

Read the last paragraph in this link power supply - Disconnecting ATX PSU's ground from mains earth to protect my oscilloscope - Electrical Engineering Stack Exchange


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## OkieDan (Nov 11, 2022)

Arbër said:


> Dude the Ground in DC is *The Negative(-) lead!.....If you were to short (Ground negative-) To mains earth your'd trip the breaker!*
> _Something tells me you don't know much about electricity (I'm an eletrician by profession btw !).
> 
> 
> No hard feelings fam.  I have another thread about cooling fans you can help me with ._



In the US at least, Earth ground goes to a metal rod in the Earth and enters your PSU via a ground conductor on power cable and terminates on the metal shell of the PSU.  The PSU DC circuit also uses that shell for DC ground/common/0V.   There should be zero potential between Earth ground and DC ground based on what these words represent in the US.

You'd at most see sparks if you run -12V DC to ground, but even that won't draw enough current to trip a breaker in the breaker panel.  My RM1000x PSU only provides DC 0.8A to -12V, that's not enough current to to heat up a wire of the gauge you'd typically find on an ATX 20(+4) connector.


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## delshay (Nov 11, 2022)

OkieDan said:


> In the US at least, Earth ground goes to a metal rod in the Earth and enters your PSU via a ground conductor on power cable and terminates on the metal shell of the PSU.  The PSU DC circuit also uses that shell for DC ground/common/0V.   There should be zero potential between Earth ground and DC ground based on what these words represent in the US.



At long last someone with sense thank you,   ..you have an up vote.

As a side note I'm in the UK, but it makes no difference, it's all done internally inside the PSU.


Arbër said:


> It's weird because in EU the ground negative DC must be physically insulated from the earth connector otherwise it will spark violently basically a dead short!.
> 
> 
> I want you to try this:
> Run a thin wire from your car battery's negative lug and touch it to the earth pin of your garage outlet!



If I was you, I would ask for a refund from whoever trained you. I don't believe you are even an electrician.

I have zero qualification & an IQ of only 12. Trust me, I'm a very dumb person & barely scrap by day to day. To tell you the truth, I'm a slacker & a bum.


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## GordonFreemanInTheFlesh (Nov 11, 2022)

delshay said:


> At long last someone with sense thank you,   ..you have an up vote.
> 
> As a side note I'm in the UK, but it makes no difference, it's all done internally inside the PSU.
> 
> ...





delshay said:


> At long last someone with sense thank you,   ..you have an up vote.
> 
> As a side note I'm in the UK, but it makes no difference, it's all done internally inside the PSU.
> 
> ...


From my point of view if you spliced DC negative to earth you would be sending/loosing electrons it may not spark or trip a breaker but most likely you will be putting unnecessary load to your psu eitherway I will check now.

I'live in Germany if you're wondering.

Edit:
I stand corrected!!
Wven though in theory earth does not benefit DC apliances with voltages lower than 50v DC.
Thank you all!


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## delshay (Nov 11, 2022)

Arbër said:


> From my point of view if you spliced DC negative to earth you would be sending/loosing electrons it may not spark or trip a breaker but most likely you will be putting unnecessary load to your psu eitherway I will check now.
> 
> I'live in Germany if you're wondering.
> 
> ...



If you look at the link, I provided earlier in this thread you can see earth wire "mains input" & ground output which is marked as earth are connected.

If I was to connect a multimeter the mains earth wire & the other end to the ground output of the PSU would I see any voltage. The answer is no. If it's zero Ohms then it's a short.


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## GordonFreemanInTheFlesh (Nov 11, 2022)

delshay said:


> If you look at the link, I provided earlier in this thread you can see earth wire "mains input" & ground output which is marked as earth are connected.
> 
> If I was to connect a multimeter the mains earth wire & the other end to the ground output of the PSU would I see any voltage. The answer is no. If it's zero Ohms then it's a short.


Yep (facepalm) silly me :S


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## Ahhzz (Nov 12, 2022)

Locked per OP request    thanks everyone!


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