One power connector vs 2?

[Coputernewbie]

I had a hard time finding a post specifically answering if one connector was worse than two connectors for overclocking.
I just ordered an EVGA 1070ti which I plan to OC. It has one 8pin. I was looking to see if there were any 2 connector 1070ti's for my price of $469 but didnt find any. I placed my order but looked again today and MSI has their DUKE model.

Will I see a difference in how much I can OC my EVGA GeForce GTX 1070 Ti SC GAMING vs the MSI DUKE
Thank you.

 

[william p]

1- 6 pin is 75W, 1-8PIN is 150W, so 2x6 pin is 150W, the same thing. They both have the same 3 -12V. wires. The 6 pin only uses 2 of them. On a single rail PSU you can use a 6 to 8 pin adapter. The 8 pin has an extra gound, and an extra signal wire.
Some multirail (OEM) PSUs only supply 75W to the 6 pin cable so then it won't work.

 

[TJ Hooker]

Technically with one 8 pin connector you can go pull up to 225W (150W from the connector, 75W through the PCIe slot itself) according to the PCIe spec. In reality, you could probably pull more, PCIe power connectors are rated for a fair bit less current than what the wires are actually capable of carrying. However, given that all 1070 Ti's are voltage locked AFAIK, you'll probably run into a voltage limit before you hit the power limit of the connectors. Depending on how much you're able to adjust the power limit of the card, you may also hit a BIOS power limit before you hit the limit of the power connectors.

TL;DR
It's unlikely your overclock will be hampered in any significant way by only have on one 8 pin connector.

 

[Eximo]

Power is certainly not an issue with Pascal cards. Given slower memory and one less shader, it should be in a pretty good position to use all the rated input. I believe most reference boards are limited to 217W input.

My reference 1080 board goes about as fast as most of the custom PCBs. (2114Mhz, 10388Mhz memory) Not a bad power delivery design actually. I think a lot of EVGAs custom boards simply doubled the number of VRMs and called it a day.

 

[Coputernewbie]

Technically with one 8 pin connector you can go pull up to 225W (150W from the connector, 75W through the PCIe slot itself) according to the PCIe spec. In reality, you could probably pull more, PCIe power connectors are rated for a fair bit less current than what the wires are actually capable of carrying. However, given that all 1070 Ti's are voltage locked AFAIK, you'll probably run into a voltage limit before you hit the power limit of the connectors. Depending on how much you're able to adjust the power limit of the card, you may also hit a BIOS power limit before you hit the limit of the power connectors.

TL;DR
It's unlikely your overclock will be hampered in any significant way by only have on one 8 pin connector.

Thanks for the great response. Im just a little concerned because this post: http://www.overclock.net/a/gpu-and-cpu-power-connections , under "The GPU power connectors" header is a little different. Saying Ill only be able to draw 195. But that seems a little low from the draws Ive seen form benchmarks and things but still within the 180w the card says it uses. Granted, the post is a little old.
All that said, Ill be using a z370 OC focused motherboard so I assume Ill be able to tweak the limitations. Using Afterburner, EVGA's personal software, or the BIOS if I can.

 

[william p]

I suppose if you were to go way outside the 150W rating then 2 connectors with 6-12V wires would have an advantage. But you have to use whatthe GPU provides and 8 pin is the fashion now.

 

[Coputernewbie]

Sorry for the downvote. Tried to figure out how to reply on mobile. No luck. Anyway, I'm not sure what you mean william

 

[william p]

The 8 pin uses the same 3 wires taht the 6 pin doe,s so fi you overload it until the wiring and connector become the limiting factor 2X 6 pin has 2x more wires and connectors than the 8 pin to distribute the heat. The 6 pin actually USES 2x 12V. wires, the 8 pin 3x wires, and 2x6 pin uses 4x 12V. wires. The 8 pin at rating can draw 50W per wire. if you needed 70W per wire the 8 pin would handle 210W, the 2x6 pin could handle 280W.

 

[TJ Hooker]

Thanks for the great response. Im just a little concerned because this post: http://www.overclock.net/a/gpu-and-cpu-power-connections , under "The GPU power connectors" header is a little different. Saying Ill only be able to draw 195. But that seems a little low from the draws Ive seen form benchmarks and things but still within the 180w the card says it uses. Granted, the post is a little old.
All that said, Ill be using a z370 OC focused motherboard so I assume Ill be able to tweak the limitations. Using Afterburner, EVGA's personal software, or the BIOS if I can.

I don't know who that guy is or where he's getting his information, but I'm looking at the PCIe spec right now and it's saying 75W from the slot, 75W from a 6 pin connector, and 150W from an 8 pin connector. From PCI Express® 225W/300 W High Power Card Electromechanical Specification Revision 1.0

A 225 W add-in card can receive power by one of the following methods:
● 75 W from the x16 PCIe connector plus 150 W from a 2 x 4 connector.
● 75 W from the x16 PCIe connector plus 75 W from a 2 x 4 connector plus 75 W from a
2 x 3 connector.
● 75 W from the x16 connector plus 75 W from a first 2 x 3 connector plus 75 W from a
second 2 x 3 connector.

 

[william p]

I was talking about going over spec. in an overclock situation. Even at spec. ( and I'm talking about the load on the wiring, and the rating of the connector).
There are 3x 12V. wires in an 8 pin PCIe cable. You will need to look at the pinout to confirm this. That means it's rated for 50W per wire. 3X50W=150W.
The 6 pin connector if you look at the pinout only uses 2 of the 12V wires, The one in the middle can be left out and sometimes is. So at the same load on the wiring and connector it can support 100W without an overload. So 2x 6 pin connectors can support 200W without exceeding the wiring and connectors normal load limits.
i don't know who you are either. Perhaps the intentional overload in my example made it more complicated than necessary.
The use of this would be if you got a 225W card installed, and you needed more power for an overclock. then the 2x6 card would be prefered over the 8pin card.

At CPUZ I'm Retrorockit. I'm pretty good at overloading things. I'm going to have to respond to that ASUS P5 that took 2nd place from me a couple days ago.
http://valid.x86.fr/top-cpu/496e74656c28522920436f726528544d29322045787472656d652043505520513638303020204020322e393347487a

 

[Eximo]

PCIe cabling standards are "suggestions", when it comes to power at least. The actually current carrying capability of the wire is down to the material and its thickness.

Many PSU vendors go with a thicker gauge wire and run a pair of PCIe 8-pin connectors, or an 8-pin + 6-pin off of a smaller number of wires.

75W for a 6-pin is very conservative with 18 gauge copper stranded wire. The idea behind the standard is to prevent excessive wire heating, which increases voltage droop via resistance. For longer PCIe cables the wire should get thicker as well, typically what you will find on the very high wattage power supplies.

It depends on a lot of factors, the gauge of the wire being the most important, and if the pins are crimped or soldered. I would say your worst PSU cabling can handle the specification, but likely handle a lot more power, and high quality stuff can easily go way beyond that.

 

[TJ Hooker]

@william p I wasn't talking to you. I was talking about the guy who posted the info in the link the OP provided, hence me quoting the OP. http://www.overclock.net/a/gpu-and-cpu-power-connections
The guy in that link is claiming that 6 pin connectors provide 80W, and 8 pin provide 120W.

 

[william p]

I'm sorry for the confusion, but it came right after my response so it thought you meant me. But the clarification may have been useful anyway.