EVGA 1080ti ,second power cable using a 6 pin from PSU to 8 pin on GPU

Hi,

I have some EVGA 1080 Ti 11GB’s and so far I have just had them powered by one 8 pin cable that splits off into two 6+2 at the end. I plug both the 6+2’s into the two 8 pins on the card and the other end into the PSU. I understand doing this I am not giving sufficient power to permit overclocking etc.

I don’t have any more 8 pin outputs spare on my PSU that would let me run a second 8 pin from PSU to the second 8 pin on the GPU, so I am wondering if I could just run a 6 pin as I have spare 6 pins available, so I would then have one 8 pin from PSU going to one 8 pin on the GPU and one 6 pin from PSU going to the other 8 pin on the GPU.

Since the card does work ok with just one 8 pin, would the additional of the extra power by 6 pin work and be safe to do?

first question: what is your psu wattage wise?
Second: why not just buy additional cables from the OEM and do it correctly

and powering your gpu outside of manufacture guidelines can damage the gpu and void the warranty

I have two Corsair CS850M which are gold rated. One is powering two GPUs and the CPU, the mobo power is split between both and the second GPU is powering two GPUs. All are 1080Ti.

The cable that came with the PSU for the GPU power was 8 pin one end and two 6+2 at the other end. At present I have the 8 pin plugged into the PSU and the two 6+2’ at the other end plugged into the two 8 pin inputs on the 1080Ti.

It works, but I have to limit the power to the GPUs to 190w each in Simple Mining OS, any higher and the cards crash. I read that 8 pin can carry at least 150w, but not sufficient to give full power to the card. If I disconnect one GPU and set the second to 225w, it still crashes, so I am thinking it must be a power limit somewhere.

I read that its better to power the second 8 pin input on the GPU with a separate cable direct to PSU, a second 8 pin would give another 150w, but I’d be fine with another 75w as I’m not bothered about overclocking, its more that I want stability and not rebooting several times a day due to cards crashing.

As I don’t have any more 8 pin outputs spare on the PSUs but do have some spare 6 pins, I was thinking to run a 6 pin with a converter to 8 pin and that would give an extra 75w whilst populating the two 8 pin inputs on the GPUs as they need to have 8 pins plugged in to work. I would of course get cables suitable for my PSU, i.e. Corsair.

I also note my risers are currently powered via SATA to 6 pin adapters which I am about to change to 6 pin to double 6 pin (one for each pair of risers) as I understand that is ample power and using the SATA adapter is a fire risk. I also wondered if the issue could be insufficient power going to the risers.

Hope this clarifies.

The motherboard needs to get 100% of its power from the same PSU

The gpu and riser should get its power from the same PSU

If you order this, it should resolve your limit of PSU slots and also resolve your power issue

Thanks, yes I guess my motherboard is powered by one PSU, I just have a dual adapter on.

Won’t that Type-4 cable still only take the power from one 8 pin output and split it into two 8 pins that go into the GPU? It doesn’t permit more power down the cable does it?

Or are you suggesting to add this as the cable for the second 8 pin input on the GPU? If so I don’t have enough 8 pin outputs on the PSU, I just have two 8 pin per PSU and two GPUs per PSU, or am I missing something?

Does this cable go backwards and you plug the two six pins into the PSU and the 8 pin into the GPU?

the cable is rated to carry the full load from the psu to the dual 8 pin on the gpu

Awesome thank you. I will get some of those and hopefully no more issues!