How to connect 1080ti (with 2x 8-pin PCIe as power connectors) with cable which has (6+2pin & 6pin)

Mining
1

Hey guys, I’m trying to build a 6x 1080ti rig, my first ever rig!

Following video/guides online, I bought the evga 1600w T2 psu.

It comes with 5x (8pin to 6+2pin & 6pin) cables. + some 8pin to (6+2)pin cables.

For the 8pin to 6+2pin & 6pin cable, would the card work if I use an 6 pin (female) to 8pin (male) adapter on the 6pin? Is it safe?

The adapter I’m thinking of getting has 18AWG and from a reputable company.

If this is not a viable option, what are the other safe alternatives?

2

it is not safe, you can buy additional cables directly from EVGA

3

I have a rig with 5x 1080ti and 1x 1080. I run 3 EVGA FTW hybrids with a separate 8pin to 8pin cable in each plug. I have 2 EVGA SC2 gaming hybrids on 1 8pin to 6+2pin & 6pin pigtail. The last one is an EVGA 1080 hybrid. I run that off 1 8pin to 6+2pin & 6pin with a 6pin to 8pin adapter on the 6pin pigtail. I’m also using the EVGA 1600w T2 PSU. I have not had any power fluctuations or spikes, or anything that would indicate their was a problem. I tried it after watching others on YT doing it and staying stable.

The rig is what I consider to be very stable—I’ll run it for several days at a time just passing my hand in front of the radiator fans and watching the cards for few seconds to make sure they’re all up, and checking the wallet I’m mining to to make sure they’re doing what I want them to do. The only time I usually even turn on that display is if I want to change the coin I have them mining. I lurv my hybrid “babies!” XD

4

Why do you say it’s not safe? It was my understanding that the 6pin and 8pin cables supplied by EVGA were rated to handle more than enough draw through them. I think I remember 50w per SATA cable and 75w per molex, but I don’t remember the numbers for the 6- and 8-pin cables. I’ll see if I can find them (BRB, on my phone).

5

Ok, I’m back. You may want to read through this link:

GOU mining electrical specifications

It says the specifications are 75w through the 6pin and 150w through the 8pin. HOWEVER, it also says that the wires can handle more (though I forget the wording; please check it out!).

Also, I forgot to mention before, but I run them all at about 70% TDP. The 1080 might be at 65%; I set them based on temperature and decided I didn’t want to unlock them to bump the power up. That rig runs at about 1230-1250w at the wall according to the kill-a-watt.

6

I didn’t read well enough. let me clarify

If you are using the cables from EVGA even the splitt 8 + 8 or the 8 + 6, you are fine. If you are using an adapter to make a 6pin into a 8 pin (which is what I thought I read) that is NOT fine.

EVGA is one of the few that you can use the 8+8 and the 8+6 on a gpu and there is no issues.

7

Ok I see thanks for this. I’m starting to lean towards separate 8pin to 8 pin cable in each plug too. You used 6pin to 8pin adapter on the 6pin pigtail.for the 1080, is there a reason why you did not do this for the FTW 1080ti?

How do you power your risers?

8

Unfortunately evga do not sell 8pin to 2x8pin cables.

9

Technically, EVGA recommends plugging a separate cable into each port for their GPUs. I can not tell you how much digging and searching it took to find that answer.

Also, Linus Tech Tips On YT (I think that’s the channel) did a video where he was using the pig-tailed cable on his 1080ti and it was running fine. He then switched it to using 2 separate power cables, not expecting to see any change, and was surprised to see a small bump in hashrate. In my personal experience, I’ve seen my FTWs show slightly better numbers than the SC2s, even when they were both on pig-tailed cables, so I decided to go ahead and do separate cables for them based on the Linus Tech Tips video. If I had one more port on the PSU, instead of 2 CPU ports, I would run the 1080 on 2 separate cables also.

I power the risers using the 6pin to molex cables, 2 risers powered on each chain. I read not to go over 2 per chain so they don’t draw more than the cable can handle. I wish EVGA sold 6pin to 6pin cables individually, but I feel better using EVGA’s supplies 6pin to molex than trying a 3rd-party’s cables to power them from 6pin.

10

Thanks for all the help, I know what I have to do now!