[SOLVED] 8+6 Pin power question for RX 5700 XT Sapphire Pulse

[HerbertSherbet]

I have a RX 5700 XT Sapphire Pulse. It is installed correctly. My question is about the power cables that I plug into it. I have a few available and I want to make sure I use the right ones. I have a picture linked at the bottom.

On the official Sapphire website it says this:
"System Requirement ... 1 x 8-pin Power Connector & 1 x 6-pin Power Connector. "
https://www.sapphiretech.com/en/consumer/pulse-radeon-rx-5700-xt-8g-gddr6

I have a power cable that came with my PSU that says "PCIe" on it. It has 8 pins that connect into the PSU, but two sets of 6+2 plugs. The second set of 6+2 pins are chained to the 6 pin plug.

To express the cable visually:
8 --> 6 --> 6 & 2 (with this extra 2 going unused)
8 --> 2

This makes me wonder that if I were to use this single cable to plug into all 12 pins then I would not supply enough power to the GPU because the last 6 pins are just duplicates. 8 pins into 12 pins sounds like not enough power.

I have a second PCIe cable with 6+2 pins and 8 pins into the CPU. Should I use two PCIe cables? I can plug 6+2 into the 8, tie off the extra 6+2 from the first cable, and then use the second PCIe cable to plug into the last 6 pins.

I also have another power cable that says "CPU" on it. It has 8 pins that connects into the PSU and a 4+4 pin setup on the other end. I figure that I shouldn't use this one but I wanted to say that I had it.

TL;DR: Should I use 1 PCIe cable or 2 PCIe cables or 1 CPU cable with 1 PCIe cable?

Spoiler: picture

 

[Gam3r01]

Depending on the quality of the PSU you have, a single PCIe cable should be fine for both the 8 pin and 6 pin. Some lower quality units use too small gauge wire and can overheat.
Two PCIe cables is technically preferable, so if you want to go that way its fine too. But again, depending on the PSU quality it may not matter either way.
As for the CPU/EPS connection, that should only be used for the processor, nothing else.

Side note: Your link is for a 5600, not a 5700.

 

[Dark Lord of Tech]

Never use a CPU cable on a graphics card , only PCIE.

 

[HerbertSherbet]

Depending on the quality of the PSU you have, a single PCIe cable should be fine for both the 8 pin and 6 pin. Some lower quality units use too small gauge wire and can overheat.
Two PCIe cables is technically preferable, so if you want to go that way its fine too. But again, depending on the PSU quality it may not matter either way.
As for the CPU/EPS connection, that should only be used for the processor, nothing else.

Side note: Your link is for a 5600, not a 5700.

I think I do have a good quality PSU but if it's normal to use two separate cables then that's what I want to do. I wasn't sure if that was okay. Heat was my other concern. I couldn't find the words for it but what you said was my exact concern. I also fixed that link. Thank you for catching that, it was just causing more confusion.

 

[Roans]

Hi, I'm in a similar situation using a Corsair RM650 and connecting to a 5700xt. I used a single 8-pin to 2x6+8-pin cable to hook it up. Works fine most of the time but under heavy load the system cuts power (In particular, Star Citizen). Heating isn't an issue as I've check all those temps, adjusted fan curves and even dropped max power consumption.. I'm wondering if it's the use of a single cable and wondering if you tried using two and had any success.

 

[HerbertSherbet]

Hi, I'm in a similar situation using a Corsair RM650 and connecting to a 5700xt. I used a single 8-pin to 2x6+8-pin cable to hook it up. Works fine most of the time but under heavy load the system cuts power (In particular, Star Citizen). Heating isn't an issue as I've check all those temps, adjusted fan curves and even dropped max power consumption.. I'm wondering if it's the use of a single cable and wondering if you tried using two and had any success.

I'm late but I may as well respond. I used two cables and had no problems. I have a 850 watt PSU and have so far not pushed my GPU to its max.

As far as overheating goes it's not about the GPU getting hot or the PSU getting hot but the cables themselves getting hot because they can't properly carry all the power that the GPU is pulling. Gauge refers to the thickness of the wire. I don't know what happens when too much power is pulled through too small of a copper wire but it might be causing some change in voltage or not supplying enough power when its needed.

If you can spare the time, the preparation work, and the cable I would do it because as Gam3r01 said, "[It] is technically preferable." Unfortunately I don't know if this will solve your problem or make a meaningful difference. I made this thread so that I would do things the best way the first time.