8pin GPU Power Cable. Different shape and Empty pin explanation

[Cat Graphic]

Hi there,

 

I've just bought an RTX 3080 TI from marketplace and the person gave me his power cable (top) that came with his power supply and I realized it doesn't fit with my power supply since there are different shapes. I used my old power cable for my GTX 1060 6GB, but there's 1 empty hole. I'm not sure what are the difference, but I'm kind of worried that the RTX 3080TI require all 8 holes to function correctly. Do I need to get a new Power Supply for the right pinned cable or why are there differences?

 

Also, since my new GPU require 2x 8pins, I've also heard that you should use 1 power cable for each 8pins for even power. Is that true?

 

 

Thank you.

 

[ZetZet]

Well first of all never use cables from different power supplies unless you are comfortable enough to check which wire goes where with a multimeter. Or at least have a pinout. 

 

Second all holes do not need to be populated on the power supply side. 8 pin can 100% function with just 6 pins being used on the power supply side, because two of the pins are just for sensing ground. 

 

And third you can use daisy chained cables if they are proper 16AWG daisy chained cables, if you have something like an old Seasonic unit that shipped with 18AWG daisy chained 8 pins then don't use it. 

[Spotty]

Don't mix cables from different power supplies. Use the cables that your power supply came with.

What power supply do you have?

 

The PCIe 8 pin connector has 3x 12v wires. The extra is a sense wire such is why not all of the pins on the PSU side need to be populated. 

[Cat Graphic]

12 hours ago, Spotty said:

Don't mix cables from different power supplies. Use the cables that your power supply came with.

What power supply do you have?

 

The PCIe 8 pin connector has 3x 12v wires. The extra is a sense wire such is why not all of the pins on the PSU side need to be populated. 

Ah, not mixing cabels from different power supply is a good thing to know. Never though there would be differences.

 

I have a Antec 850 w - High Current Gamer ATX12V/EPS12V. I had a friend that came by with his Corsair cable and it indeed not fit. It seems that all the bottom pins have a bevel on the bottom and won't accept the square ones. This power supply have 2x 12v connectors.

 

I'm trying to find a single Antec PCIe cable, but there seems to not be any on Amazon. Only pack of multiple ones. Are there any other cable that are compatible or am I only restricted to Antec PCIe. If so, do I have to just buy a new Power Supply?

 

 

 

Thanks a lot for the help!

[Cat Graphic]

12 hours ago, ZetZet said:

Well first of all never use cables from different power supplies unless you are comfortable enough to check which wire goes where with a multimeter. Or at least have a pinout. 

 

Second all holes do not need to be populated on the power supply side. 8 pin can 100% function with just 6 pins being used on the power supply side, because two of the pins are just for sensing ground. 

 

And third you can use daisy chained cables if they are proper 16AWG daisy chained cables, if you have something like an old Seasonic unit that shipped with 18AWG daisy chained 8 pins then don't use it. 

That's interesting to know that there are ground pins even if they are filled or empty.

How do you measure the cables to be 16 AWG? I've seen this online and thought I should probably get a 2nd PCIe cable since I'm currently using the last bottom picture one by splitting. Only thing is that I can't find a single cable compatible with my Antec power supply, so I'm wondering if I'm fine or I should change power supply.

 

[ZetZet]

18 minutes ago, Cat Graphic said:

That's interesting to know that there are ground pins even if they are filled or empty.

How do you measure the cables to be 16 AWG? I've seen this online and thought I should probably get a 2nd PCIe cable since I'm currently using the last bottom picture one by splitting. Only thing is that I can't find a single cable compatible with my Antec power supply, so I'm wondering if I'm fine or I should change power supply.

Yeah, this image was posted by Seasonic, because their older units shipped with inadequate cables which couldn't handle daisy chained 8 pins. 

 

Wire gauge is usually marked on the cable. Or you can google your unit and look for reviews, they usually have an overview of the cables. 

[Cat Graphic]

16 minutes ago, ZetZet said:

Yeah, this image was posted by Seasonic, because their older units shipped with inadequate cables which couldn't handle daisy chained 8 pins. 

 

Wire gauge is usually marked on the cable. Or you can google your unit and look for reviews, they usually have an overview of the cables. 

Ohh that's specifically for Seasonic products.

 

I'm not sure which brand the PCIe cable is, but it's written 18AWG. Do I really need a 16 AWG? If so, I guess i'll have to buy a new Power Supply since I can't seem to find a new cable.

 

 

[ZetZet]

21 minutes ago, Cat Graphic said:

Ohh that's specifically for Seasonic products.

 

I'm not sure which brand the PCIe cable is, but it's written 18AWG. Do I really need a 16 AWG? If so, I guess i'll have to buy a new Power Supply since I can't seem to find a new cable.

Your unit is pretty old so it doesn't have proper 300W daisy chained cables.

 

Did you buy it as a prebuilt or did you lose the cables? Since it should have had 2 cables in the box originally. 

[Cat Graphic]

34 minutes ago, ZetZet said:

Your unit is pretty old so it doesn't have proper 300W daisy chained cables.

 

Did you buy it as a prebuilt or did you lose the cables? Since it should have had 2 cables in the box originally. 

I was given the case with power supply from my oncle. It's indeed old. I only found 1 cable with it.

 

I got the RTX 3080ti from someone and was given his power supply cable, which didn't fit mine.

 

If I use this current cable, what will happen? Should I get  new Power Supply in case?

[ZetZet]

1 hour ago, Cat Graphic said:

I was given the case with power supply from my oncle. It's indeed old. I only found 1 cable with it.

 

I got the RTX 3080ti from someone and was given his power supply cable, which didn't fit mine.

 

If I use this current cable, what will happen? Should I get  new Power Supply in case?

The card will work, however pulling over 8 amps through 18 awg cable is not advisable. The cable/connectors will heat up during longer game sessions.

[Cat Graphic]

4 hours ago, ZetZet said:

The card will work, however pulling over 8 amps through 18 awg cable is not advisable. The cable/connectors will heat up during longer game sessions.

Thanks for letting me know about thr AWG cable and requiring 1 cable each port. I went ahead and got a 1000W power supply with 5th gen pcie cable and 1 in each 8 pins. Works great so far!

 

 

[nosys70]

you have to know that PCI-E cables are almost all the same.

A standard PCI-E cable has only 2 things passing inside , the ground wire and the +12V.

A standard 6 pins is supposed to sustain 75W and a 8 pins 150W.

But most GPU today are using a ot more, so more than one connector is needed.

 

So you could get a Y cable with dual 6 pins =150W (75+75)

you could also get an Y with dual 6+2 pins =300W (150+150)

It is very common to find cable with dual connectors but not an Y cable, instead you get the second connector extended (daisy chained) from the first one.

usually the 2nd connector is only 75W, so it is not recommended with power hungry GPU. 

Then you get a 225W cable (150+75).

If you get a real high end card. using true 6+2 Y cable gives you all the power you need, else the card could throttle to low power mode.

 

Additionally, some pins are used to sense the power available (there are 2 ground pins that are sense A and B).

Depending if these pins are wired to ground or not, the card will detect the cable differently.

 

That is why you could get a 8 pins connector with missing pins, because it is in fact wired as a 6 pins with lower power.

 

Some PSU maker could use a different pinout on the PSU, so even if the pinout is standard from the GPU side, it is not from the PSU side.

That is why it is not recommended to use the cables from another PSU. In cas of doubt, you can simply plus the cable in the PSU and make sure the GND and +12V

are where they should be.

You can also efect the pins from the case with proper tool and re-pin the connector for your needs.