Question Can anyone explain how two 8-Pin PCIe ports supply 600 watts?

[Cameron R]

I have spent two full days trying to understand how two 8-pin PCIe connection ports on the ROG Thor 1200P2 Gaming PSU can supply 600 watts to a GPU.

The cable that comes with the PSU has one end with two 8-pin connectors and the other end a 12VHPWR connector with markings that say "600 watts." This cable is an afterthought, obviously, since the PSU was made before anyone needed or wanted 600 watts, and it's just tossed in the PSU's box.

It's my understanding that each 8-pin PCIe port on this PSU is capable of supplying 150 watts, which doubled, is 300.

So, for 600 watts to actually pass through that cable, there would need to be four such 8-pin connectors all connected to a 150 watt port.

Some guy online answers the question by saying, well there are more wires and grounds in the 12VHPWR cable so therefore 600 watts get supplied.

I find that to be a fantastic miracle. We can manufacture power simply by adding wires and grounds. How interesting.

Now, if this PSU supplies MORE than 150 watts per 8-pin connection... but I can't find anyone even at ASUS who can answer this question.

I must be missing something.

And a follow-up: Are there any benefits to getting a PSU made to the ATX 3.0 or 3.1 spec in terms of the "sense" wires that come with the newest 12V-2x6 cables?

Obviously I'm not an expert on this... but I am trying to understand.

 

[Eximo]

The PSU end is not the same as the PCIe 8-pin output which I think is where your confusion comes from.

It is quite common for a heavier gauge wire to be used to connect a single 8-pin connector at the PSU side to dual 8-pin PCIe connectors at the GPU side. That is how you get PSUs with 8 or more PCIe cables coming out of them. Not usually enough room at the PSU side for straight through connectors to every point in a potential system. Why you see multiple connectors on the end of almost every cable.

22 gauge wire is typical in lower end PSUs. Higher end units can do as large as 16 gauge wire which has a much higher current capacity.

1x PCIe = 150W (really more like 180W since it is three 12V wires)
2 x dual 8-pin PCIe cables from the PSU = 600W.
A single 12VHPWR cable is rated at 600W with six 12V wires.
The new 12-pin cable is uprated to 675W. They supposedly increased the contact area of the pins.

 

[hotaru.hino]

The cable that comes with the PSU has one end with two 8-pin connectors and the other end a 12VHPWR connector with markings that say "600 watts." This cable is an afterthought, obviously, since the PSU was made before anyone needed or wanted 600 watts, and it's just tossed in the PSU's box.

It's my understanding that each 8-pin PCIe port on this PSU is capable of supplying 150 watts, which doubled, is 300.

So, for 600 watts to actually pass through that cable, there would need to be four such 8-pin connectors all connected to a 150 watt port.

A lot of higher end PSUs will have a PCIe power cable that connects to one port on the PSU and terminates as two 8-pin connectors. So they can deliver 300W via one cable. And they can get away with that by using a cable with thicker individual cables that can carry more current safely.

If your PSU didn't come with the older PCIe power connectors, then it's likely ASUS recycled an existing design that did and threw in a 12VHPwr cable that has the sense pins configured in a way that the GPU will always think 600W is available.

 

[Cameron R]

The PSU end is not the same as the PCIe 8-pin output which I think is where your confusion comes from.

It is quite common for a heavier gauge wire to be used to connect a single 8-pin connector at the PSU side to dual 8-pin PCIe connectors at the GPU side. That is how you get PSUs with 8 or more PCIe cables coming out of them. Not usually enough room at the PSU side for straight through connectors to every point in a potential system. Why you see multiple connectors on the end of almost every cable.

22 gauge wire is typical in lower end PSUs. Higher end units can do as large as 16 gauge wire which has a much higher current capacity.

1x PCIe = 150W (really more like 180W since it is three 12V wires)
2 x dual 8-pin PCIe cables from the PSU = 600W.
A single 12VHPWR cable is rated at 600W with six 12V wires.
The new 12-pin cable is uprated to 675W. They supposedly increased the contact area of the pins.

My question isn't how much current the wire can handle. My question is how much current can the 8-pin ports provide? If each port can provide roughly 150 watts, to get 600, the cable would need four (4) connectors on the PSU end and a 12VHRWR at the GPU end.

 

[Cameron R]

A lot of higher end PSUs will have a PCIe power cable that connects to one port on the PSU and terminates as two 8-pin connectors. So they can deliver 300W via one cable. And they can get away with that by using a cable with thicker individual cables that can carry more current safely.

If your PSU didn't come with the older PCIe power connectors, then it's likely ASUS recycled an existing design that did and threw in a 12VHPwr cable that has the sense pins configured in a way that the GPU will always think 600W is available.

You seem to be confirming my thoughts. But I'm trying to get this cleanly stated. So here is the question: How much power can each 8-pin PCIe port on the ROG THOR 1200P2-Gaming provide?

 

[hotaru.hino]

You seem to be confirming my thoughts. But I'm trying to get this cleanly stated. So here is the question: How much power can each 8-pin PCIe port on the ROG THOR 1200P2-Gaming provide?

Those technically aren't 8-pin PCIe ports to begin with. If the only GPU cable ASUS supplied you with was a 600W 12VHPwr one that connects to two of the ports on the PSU, then it's reasonable to assume that the ports can handle up to 300W.

And if they don't, well good luck with the RMA.

 

[Wolfshadw]

Each 8-Pin PCI-E GPU Power port can provide up to 150 watts of power. The 12VHPWR connector can provide (this is where the confusion is) UP TO 600 watts of power, assuming there are FOUR 8-pin PCI-E power connectors at the other end. Since yours only has two, only (up to) 300 watts of power is provided.

-Wolf sends

 

[35below0]

Maybe because it doesn't actually deliver 600w?

I have seen this mentioned in several hwbusters reviews. Here is one of them: https://hwbusters.com/psus/thermaltake-toughpower-gf3-1000w-atx-v3-0-psu-review/
"According to the ATX spec, a 1000W PSU should come with a 450W 12VHPWR connector, but no one has followed this rule so far. All brands and manufacturers provide 600W cables because it is easier to keep track of their inventories with only a single type of 12+4 pin connector."

Apologies if i misunderstood something. I don't know enough about PSU internals and workings to lecture anyone.

Each 8-Pin PCI-E GPU Power port can provide up to 150 watts of power. The 12VHPWR connector can provide (this is where the confusion is) UP TO 600 watts of power, assuming there are FOUR 8-pin PCI-E power connectors at the other end. Since yours only has two, only (up to) 300 watts of power is provided.

-Wolf sends

That would explain the mystery. Are there any GPUs on the market with 4 connectors? I know some have 3.

 

[Cameron R]

Those technically aren't 8-pin PCIe ports to begin with. If the only GPU cable ASUS supplied you with was a 600W 12VHPwr one that connects to two of the ports on the PSU, then it's reasonable to assume that the ports can handle up to 300W.

And if they don't, well good luck with the RMA.

I'm not sure I understand. The ports are 8-pin. And they are labeled PCIe. So how are they not "technically" 8-pin PCIe ports?

Others seem to assume that each port can provide only 150 watts. I'm sure the marketing department would like us to assume all sorts of great things... Yet... Nothing on any documentation that I've seen (and none came with the PSU) indicates wattage available per port... So I'm still at a loss...

 

[Cameron R]

Each 8-Pin PCI-E GPU Power port can provide up to 150 watts of power. The 12VHPWR connector can provide (this is where the confusion is) UP TO 600 watts of power, assuming there are FOUR 8-pin PCI-E power connectors at the other end. Since yours only has two, only (up to) 300 watts of power is provided.

-Wolf sends

Yay!!!!! Thank you! As I suspected. So this baby is going back. Marketing BS. My God it's been hard to get this information clearly stated.

As I said, one guy from a review acclaimed that all the extra wires and ground somehow increased (doubled) the power transmitted. I knew if that were true, we had stumbled on a miracle akin to the Flux-Capacitor in Back to the Future...

And not surprisingly, even ASUS technical support told me that the miracle cable increased the power to 300 watts per port. When I questioned it, he said, and I quote "you are railroading me. Of course it supplies 600 watts. I'm terminating this conversation."

 

[hotaru.hino]

I'm not sure I understand. The ports are 8-pin. And they are labeled PCIe. So how are they not "technically" 8-pin PCIe ports?

Pin count means nothing. The biggest hint it's technically not PCIe is that ASUS expects you to plug in an EPS12V cable in one of those ports. 8-pin EPS12V is expected to supply up to 336W. In addition, EPS12V uses 4x12V lines, whereas PCIe uses 3, regardless of pin configuration.

I did look around to see if I could find the contents of the PSU, but none of them really laid it out or wrote down what was in the package. I found a review of the previous version of this PSU and found it came with both "dedicated" PCIe power cables and ones with pigtails. A pigtailed cable must be able to handle 300W from the connector and that cable doesn't plug into two spots on the PSU. The only reason why a dedicated cable would be useful is if you're doing extreme overclocking and a pigtail cable can cause issues in those scenarios.

Also again if ASUS included a 12VHPwr cable that is rated for up to 600W and there's only two connectors to plug into the PSU, then one of these two outcomes apply here:

• ASUS was hoping nobody would plug this into an RTX 3080/4080 or RTX 3090/4090
• The connectors on the PSU can supply enough wattage safely

And they specifically advertise a 600W cable, so if a company is advertising that but is hoping nobody actually tries it, then there's some serious issues going on here. (well, it is ASUS we're talking about here...)

 

[Cameron R]

Pin count means nothing. The biggest hint it's technically not PCIe is that ASUS expects you to plug in an EPS12V cable in one of those ports. 8-pin EPS12V is expected to supply up to 336W. In addition, EPS12V uses 4x12V lines, whereas PCIe uses 3, regardless of pin configuration.

I did look around to see if I could find the contents of the PSU, but none of them really laid it out or wrote down what was in the package. I found a review of the previous version of this PSU and found it came with both "dedicated" PCIe power cables and ones with pigtails. A pigtailed cable must be able to handle 300W from the connector and that cable doesn't plug into two spots on the PSU. The only reason why a dedicated cable would be useful is if you're doing extreme overclocking and a pigtail cable can cause issues in those scenarios.

Also again if ASUS included a 12VHPwr cable that is rated for up to 600W and there's only two connectors to plug into the PSU, then one of these two outcomes apply here:

• ASUS was hoping nobody would plug this into an RTX 3080/4080 or RTX 3090/4090
• The connectors on the PSU can supply enough wattage safely

And they specifically advertise a 600W cable, so if a company is advertising that but is hoping nobody actually tries it, then there's some serious issues going on here. (well, it is ASUS we're talking about here...)

I can't figure out how to get a picture here... But the PSU has 8 ports labeled CPU/VGA/PCIe. Those are all 8-pin. The other ports are 6 pin, and the MB ports. Nothing is labeled EPS12V, if that matters. And no way do I trust a marketing department's claims...

 

[Cameron R]

 

[hotaru.hino]

I can't figure out how to get a picture here... But the PSU has 8 ports labeled CPU/VGA/PCIe. Those are all 8-pin. The other ports are 6 pin, and the MB ports. Nothing is labeled EPS12V, if that matters. And no way do I trust a marketing department's claims...

CPU is EPS12V.

And in this case, marketing advertising the 600W cable isn't something they can stretch the truth on. If the PSU blows up because someone actually tried using the cable with an RTX 4090, then that's a legal liability. It's not like Intel or AMD saying a CPU can get up to 5.0GHz but conveniently not point out that it only happens when doing single core workloads. They can still prove the CPU can reach that clock speed and it's not a legal liability that the CPU can't do that in multi-core workloads.

In any case, if you haven't emailed ASUS support, then do that. Get an answer from the manufacturer itself.

And if you still don't want to believe them, fine. Ditch the PSU and get another one.

 

[Cameron R]

CPU is EPS12V.

And in this case, marketing advertising the 600W cable isn't something they can stretch the truth on. If the PSU blows up because someone actually tried using the cable with an RTX 4090, then that's a legal liability. It's not like Intel or AMD saying a CPU can get up to 5.0GHz but conveniently not point out that it only happens when doing single core workloads. They can still prove the CPU can reach that clock speed and it's not a legal liability that the CPU can't do that in multi-core workloads.

In any case, if you haven't emailed ASUS support, then do that. Get an answer from the manufacturer itself.

And if you still don't want to believe them, fine. Ditch the PSU and get another one.

The PSU wouldn't blow up from being underpowered. That much I know.

I talked to them. But they would not connect me with anyone who knew anything about PSUs. It's not a matter of disbelieving someone speaking from knowledge. It's a matter of questioning someone who says, well, I "assume..."

I'm a lawyer by profession. I do not accept assumptions. Nor do I believe advertising copy.

And the guy who wouldn't refer me to someone more knowledgeable was simply not sufficiently versed to be believable. He'd make a lousy witness...

For example, he did NOT say, hey, this is a EPSD12V port that supplies more than 150 watts. He never said anything to that effect.

How can we know the difference between a 150 watt 8-pin port and a 300+ watt 8-pin port?

 

[hotaru.hino]

The PSU wouldn't blow up from being underpowered. That much I know.

I talked to them. But they would not connect me with anyone who knew anything about PSUs. It's not a matter of disbelieving someone speaking from knowledge. It's a matter of questioning someone who says, well, I "assume..."

I'm a lawyer by profession. I do not accept assumptions. Nor do I believe advertising copy.

And the guy who wouldn't refer me to someone more knowledgeable was simply not sufficiently versed to be believable. He'd make a lousy witness...

For example, he did NOT say, hey, this is a EPSD12V port that supplies more than 150 watts. He never said anything to that effect.

How can we know the difference between a 150 watt 8-pin port and a 300+ watt 8-pin port?

Then we should end the thread here.

Unless any of us has the PSU you have and professional grade test equipment to verify its capabilities, we cannot give you the answer that you, as a lawyer, would like. It's all assumptions because we don't have a way to verify what you want. And even then, what would be acceptable proof? A live stream of the footage?

 

[Cameron R]

Then we should end the thread here.

Unless any of us has the PSU you have and professional grade test equipment to verify its capabilities, we cannot give you the answer that you, as a lawyer, would like. It's all assumptions because we don't have a way to verify what you want. And even then, what would be acceptable proof? A live stream of the footage?

Say what? You seem offended. I apologize.

I'm not challenging you. I'm simply asking how I can know what this unit does? I just need someone to explain it. You say it's over 300. Okay, good. So my question is, how can I discern that? And why on earth would the people--who ARE in a position to know--not tell me that? Well, as I said, the ASUS guy was clueless as to these PSUs. Even when I asked to speak with an expert, who could have solved my quandary by simply saying, "Oh, hey, those are EPSD12V ports that supply over 300 watts each--says right here in the official owner's manual... "

I've been at this for literally days now. And I have not found a source anywhere that explains. Or says, hey, these are 150 watt ports, these are 300 watt ports. And here is how you can tell...

Do you know where I can read about the different power supplied by the various ports? And can you tell me why this ROG unit is silent on the issue? I'm not challenging you. I'm just asking for help.

 

[Zerk2012]

You seem to be confirming my thoughts. But I'm trying to get this cleanly stated. So here is the question: How much power can each 8-pin PCIe port on the ROG THOR 1200P2-Gaming provide?

Your opening a great big can of worms.
A 6 pin connector can only supply 75 watts (but it has 3 positive wires just like a 8 pin) so how can a 8 pin deliver 150 watts. Now if you look at my Seasonic it has a pigtail coming off each 8 pin connector ( it plugs into a single 8 pin connector on the PSU) the pigtail is just some of the wires jumped from one connector at the end of the cable to another 8 pin connector but it's rated for 225 watts using the pigtail that goes to a single 8 pin on the PSU how is that possible.

Unless you know the exact gauge wire used in the cable that plugs into the PSU and the exact gauge wires on the inside of the PSU and how it's configured then all you can do is go by what the manufacture says.

In this specific case.

PCIe® Gen 5.0 Ready​

Each ROG Thor 1200 W Platinum II PSU is bundled with a 16-pin PCIe® cable that can pipe up to 600 W of power to PCIe® Gen 5.0 graphics cards. Get ready for the future of power delivery.

Says 600W on the cable even.

https://cdn.cs.1worldsync.com/syndi...611f0c09593b3eafb893fbe35f16cfab/original.png

EDIT. For what ASUS says over the phone or anywhere else that's another story personally I would NEVER buy any ASUS product. I rather just pay sales tax without the added ASUS name tax for usually inferior gimmick products with con men for support and warranty.

And why on earth would the people--who ARE in a position to know--not tell me that? Well, as I said, the ASUS guy was clueless as to these PSUs

All ASUS support people are clueless about everything.

 

[35below0]

That is personal bias and has nothing to do with quality and capabilities of the PSU in question. It's not made by ASUS anyway. Almost all PSUs are made by a handful of manufacturers.

This one might have an extra cost to it and it may be gimmicks but overall it's a good PSU.

 

[Zerk2012]

That is personal bias and has nothing to do with quality and capabilities of the PSU in question. It's not made by ASUS anyway. Almost all PSUs are made by a handful of manufacturers.

This one might have an extra cost to it and it may be gimmicks but overall it's a good PSU.

No your still paying a extra ASUS tax for a PSU you can get for less with the same quality.

Most of the PSU makers are willing to now build a PSU to the specks the buyer ask for letting them determine the parts used etc..

This has been going on now for a while.

That is made by Seasonic and the first listed con is the price or Asus tax.

Cons​

• -
  Expensive
• -
  Not as efficient as competition
• -
  OPP is set sky-high
• -
  Bulky

EDIT No personal BIAS just the fact that anybody that buys a ASUS product is overpaying for a garbage company that has no customer service worth calling and you send it in for warranty (this is from experience that some people her don't have) you get it back with the same exact problem or they say it's damaged and will charge you to even send it back (not working) to you.

From the OP experience with ASUS joke of service and product knowledge>

And why on earth would the people--who ARE in a position to know--not tell me that? Well, as I said, the ASUS guy was clueless as to these PSUs

 

[35below0]

No your still paying a extra ASUS tax for a PSU you can get for less with the same quality.

Most of the PSU makers are willing to now build a PSU to the specks the buyer ask for letting them determine the parts used etc..

This has been going on now for a while.

That is made by Seasonic and the first listed con is the price or Asus tax.

Cons​

• -
  Expensive
• -
  Not as efficient as competition
• -
  OPP is set sky-high
• -
  Bulky

EDIT No personal BIAS just the fact that anybody that buys a ASUS product is overpaying for a garbage company that has no customer service worth calling and you send it in for warranty (this is from experience that some people her don't have) you get it back with the same exact problem or they say it's damaged and will charge you to even send it back (not working) to you.

Fair point, but even justified bias is bias.

And you never said it's a bad PSU, because it's not. But ultimately the PSU is already bought.

It is good to hear about bad experiences and bad practises by these companies though.

 

[Zerk2012]

Fair point, but even justified bias is bias.

And you never said it's a bad PSU, because it's not. But ultimately the PSU is already bought.

It is good to hear about bad experiences and bad practises by these companies though.

And it's still overpriced for what you get, from the CONS OVERPRICED, OPP set sky high that = really not safe!

From the OP when he called people with 0 knowledge of their products.
And why on earth would the people--who ARE in a position to know--not tell me that? Well, as I said, the ASUS guy was clueless as to these PSUs

You can try to defend anything you wish I could care less but get more experience and you will open your eyes.

When you get busted over and over and lie about your products your 12 years ago good rep goes to trash.
Like their gimmick AI software with the auto overclock, you ever seen it and fixed the PC by removing that software? I have several times. Overall close to just a scam company making a killing on the overpriced junk still living off the people buying the stuff because it was at one time a good product.

 

[Eximo]

Your opening a great big can of worms.
A 6 pin connector can only supply 75 watts (but it has 3 positive wires just like a 8 pin)

The 6-pin standard does not require 3 12V wires, just two. It generally does because most 6-pin connectors in more recent power supplies are part of 6+2 PCIe connectors. The third conductor is for the 8-pin scenario, and the additional two pins are a ground and a sense wire to let the GPU know that the 8-pin is connected with all three wires.

I know it has been stated many times in half a dozen different ways, but I will lay out a scenario that may help.



If you crack open a 12VHPWR cable, you will find that the 6 12V wires and the 6 ground wires are essentially ganged together. The wires are there for flexibility.

You could replace all of these wires with one single conductor, like an 8 gauge wire or a copper bar and it would still work as long as the 4 sense pins were configured correctly.

At the PSU end you could solder that 8 gauge wire directly to the 12V output, bridging all the wire connection points.

As others have stated, the PSU is modular. EPS and PCIe being interchangeable at the PSU end. EPS 12V carries 4 12V wires, and more appropriately gets to 336W, or 84W per wire. I usually hedge my bets and assume that cheaper PSUs will have used a lighter gauge wire and say that each wire can deliver around 60W before significant droop.

ASUS, or more correctly the actual OEM of the PSU has designed the PSU backplane with that level of power delivery in mind.

On my Corsair RM850x, the cable that is sold for 12VHPWR only has two 8-pin connections at the PSU end. I would trust it just fine. Knowing that each cable I have in the included modular cable kit is a 2 x 8-pin PCIe cable. So if I got a GPU bundled with a 4 x 8-pin adapter cable, it would take two PSU cables to populate it.

 

[Cameron R]

I just found this, from PCWorld.com:

https://www.pcworld.com/article/631...upplies-their-first-overhaul-in-20-years.html

"Technically, 8-pin GPU connectors support a maximum of 150 watts, for a maximum of 450 watts on paper when you use three of them. In reality, most power supplies and most 8-pin plugs can support 324 watts (27 amps at 12 volt) or even 468 watts (39 amps at 12 volts) according to power supply maker Corsair. That, of course, depends on the power supply design. There’s no guarantee of what each PSU can support through those three 8-pin GPU plugs."

So, I have again reached out to ASUS to explain how much power each port can provide.

 

[--SID--]

Yeah, that's about the connector on a PCIe cable. In my mind you ask for the CPU/PCIe connector on the modular board of the PSU. That connectors are better quality with different pinout. The connector on the modular board is rated for 13A per pin if it's HCS or 9A if it's standard minifit je.