need information about 8pin pcie wattage

FP91G

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Quote from: mobylke on September 13, 2022, 02:17:31 AM

Hello guys,

For over a year i've been building rigs and powering gpu's based on this scheme:

But then one google search later, all information i find is that 8pin pcie cable can provide up to 150W, while the scheme says that it can provide up to 288W. If it really was only up to 150W, many of my rigs would be crashing all the time and i constantly would have to change melted connectors, although i never had any problems.

Surely i'm missing something, can someone give me some information?

First let's be clear that PCI-SIG lists the maximum rating of its 6-pin PCI-e connector at 75 watts, and its 8-pin PCI-e connector at 150 watts. That is the safe rating, and you go any higher than that at your own risk.
https://www.gpuminingresources.com/p/psu-cables.html
Cables and connectors can work at high power values, but you need to read the documentation for your equipment to assess the risks.

JayDDee

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Quote from: philipma1957 on September 13, 2022, 11:19:00 PM

a 3090 and a 3090 ti . i like two cables with two jacks each

that is 4 jacks i merge one jack from each cable to a eight pin cable.

and i use the other two jacks alone

That's an interesting way to balance the load accross 2 cables but I don't think adding connectors in series is
a good idea when drawing high power.

2x8 + 8 + slot should be good for up to 400W. That's 76% of the rated capacity, so 228 watts from the
2x8 cable, 114 from the 1x8 cable, and 57 from the slot.

philipma1957

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Quote from: mobylke on September 13, 2022, 11:04:11 AM

Thank you all for your information.

All higher-end gpus have 2 or 3 connections, so if for example i power 1x3070 which has 2 connections there should be no melted connectors? because 2 connectors would be able to support up to 300W?

If so, then this melted connector problem should only apply to really powerful cards, like 3080ti, 3090

the 3070 should never be clocked over 200 watts when mining.

so 1 cable with 2 jacks will be fine.

a 3080 does 225-250 so 1 cable is not so good
a 3080 ti does 240-280 so 1 cable is not good
a 3090 does 270-320 so 1 cable is not good.
a 3090 ti does 300-350 so 1 cable is not good.

if i run a 3080 I like using one jack eight pin cables two of them.

if I use a three jack card that pulls over 300 watts.

a 3090 and a 3090 ti . i like two cables with two jacks each

that is 4 jacks i merge one jack from each cable to a eight pin cable.

and i use the other two jacks alone

this insures half the load on each cable so a 350 watt load is 175+175 and safe

if you don’t spilt the load that way you could pull too much on one of the cables.

JayDDee

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Quote from: mobylke on September 13, 2022, 11:04:11 AM

Thank you all for your information.

All higher-end gpus have 2 or 3 connections, so if for example i power 1x3070 which has 2 connections there should be no melted connectors? because 2 connectors would be able to support up to 300W?

If so, then this melted connector problem should only apply to really powerful cards, like 3080ti, 3090

Also count the connectors vs the power rating of the GPU. Some 300W cards have 2x8 some have 3x8.
I shouldn't need to explain what that means.

rdluffy

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Quote from: mobylke on September 13, 2022, 11:04:11 AM

Thank you all for your information.

All higher-end gpus have 2 or 3 connections, so if for example i power 1x3070 which has 2 connections there should be no melted connectors? because 2 connectors would be able to support up to 300W?

If so, then this melted connector problem should only apply to really powerful cards, like 3080ti, 3090

Each situation is different, but let's suppose you're mining with a 3070, it's something like 150w from the wall with adjustments, so 2 connectors is way more than necessary.
If you are gaming or using 3080, 3090 etc and have all cables, it's better to use 2 separate cables to power your card, 2 PSU ports.

I found an interesting image, I think it's from Seasonic old manuals:

Source: https://linustechtips.com/topic/1098163-is-the-corsair-tx-m-series-650-sapphire-amd-radeon-rx-vega-56-compatible/

But now they do the manuals with a slightly difference:

Source: https://seasonic.com/pub/media/pdf/consumer/user-manual/Seasonic-installation-guide-digital.pdf

adaseb

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Quote from: mobylke on September 13, 2022, 11:04:11 AM

Thank you all for your information.

All higher-end gpus have 2 or 3 connections, so if for example i power 1x3070 which has 2 connections there should be no melted connectors? because 2 connectors would be able to support up to 300W?

If so, then this melted connector problem should only apply to really powerful cards, like 3080ti, 3090

You also have power coming from the PCIe slot, usually max 75 Watts. Average is perhaps 30-50 Watts from the PCIe slot. So if a GPU is pulling 300 Watts then from the PCIe external connectors it uses maybe 250 Watts max. Hence 2 connectors are more than safe.

Here is another thing to keep in mind. Some lower end PSUs have 2 PCIe 8 pin but they are in series not parallel. If that is the case don't connect it to that. Because it'll pull too much current from those pins.

mobylke

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Thank you all for your information.

All higher-end gpus have 2 or 3 connections, so if for example i power 1x3070 which has 2 connections there should be no melted connectors? because 2 connectors would be able to support up to 300W?

If so, then this melted connector problem should only apply to really powerful cards, like 3080ti, 3090

rdluffy

legendary

Activity: 2366

Merit: 1408

As far as I know, I remember to see something like:

6-pin cable - 75 watts
8-pin cable - 150 watts

But you have to consider that Riser or Motherboard will provide max 75w, so 40 or 50w usually will be provided by these
Your GPU will not be powered only by the cable PCIe

I'll try to find official resources, I can't remember well if I saw on Corsair's website or Seasonic

adaseb

legendary

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Generally the 6 pin is rated for 75 watts and 8 pin is for 150 watts. Only difference between the two is that the 8 pin has more ground pins.

The wire can handle all that wattage the bigger issue is the female connector pins. When you plug something in and out a few times it spreads and contacts aren’t as good and it’ll start to melt at the harness connector pins.

philipma1957

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'The right to privacy matters'

corsair
evga
seasonic

can all handle 200 watts long term

but they say 150. as some one said that is the plug.

I have used 1 eight pin wire with 2 plugs at 250 watts for long times (2-3-4 months), but they ocassionaly start to fail a bit.

some melt action .

So I try to stay at 200 watts on a cable with 2 jacks

JayDDee

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Don't confuse the connector with the cable, the connector is limited to 150W but there are usually 2 per cable.
Also cheap PSUs don't follow the spec, use flimsy cables, use 6 wires for 8 pins, poor solder joints etc.

sxemini

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Quote from: mobylke on September 13, 2022, 02:17:31 AM

Hello guys,

For over a year i've been building rigs and powering gpu's based on this scheme:

But then one google search later, all information i find is that 8pin pcie cable can provide up to 150W, while the scheme says that it can provide up to 288W. If it really was only up to 150W, many of my rigs would be crashing all the time and i constantly would have to change melted connectors, although i never had any problems.

Surely i'm missing something, can someone give me some information?

8 Pin can deliver more than 150w, but the manufacturer say only 150w for save use. It can deliver more until it burns Wink

All over 288w on the PSU side is out of the specifications / save use, but it doesn´t mean all cables must burn.

The max I do over an 8 pin (GPU side) is 225W for long term mining.

mobylke

newbie

Activity: 5

Merit: 0

Hello guys,

For over a year i've been building rigs and powering gpu's based on this scheme:

https://1.bp.blogspot.com/-vAhFuH5GdkQ/WrBq7KbWKgI/AAAAAAAAAWA/ZI0w2WI8QVYT8zkhyNbae69o5MjJtC89QCLcBGAs/s640/PCIe2.png

But then one google search later, all information i find is that 8pin pcie cable can provide up to 150W, while the scheme says that it can provide up to 288W. If it really was only up to 150W, many of my rigs would be crashing all the time and i constantly would have to change melted connectors, although i never had any problems.

Surely i'm missing something, can someone give me some information?

Topic: need information about 8pin pcie wattage (Read 118 times)