My PSU is an 850w EVGA supernova, it comes with 2x PCI power cables both are 8pin from the PSU and terminates as 8 pin (6+2) and 6 pin on each cable, the Graphics card I am looking at getting (RX 7800XT) needs 2x8pin, can I just connect 2 x PCI power cables to the PSU and use the 8pin (6+2) on each cable (leaving the 6 pin on both unused). Alternatively can I just get a new PSU cable that is 8pin from the PSU with 2 x 8pin on the other end to connect to the Graphics card?
It’s all on the 12v rail so it shouldn’t matter, should it?
yes you can use them with two different cables on the 12v rail. It’s not a problem. But be careful when buying cables for modular PSU online, just buy from the producer.
I have 2 cables that came with it (both have an 8pin and a 6pin on the GPU end so I’m just going to use both cables and just use the 8pin connector on each.
It’s been a while since I last build a PC. I should know this shit, I used to be a system builder… But that was also many years ago.
Thanks!
I feel you. I’d been out of the PC building scene for a while now, just built a new one a couple months ago.
Most things are pretty much the same, and the principles all still apply but it can be daunting at first.
I don’t know about the 8->[6+2]+[6] cable situation. I haven’t seen those. 8->[6+2] is fairly common though, as is 8->[6+2]*2 (some call it a pigtail).
The main advantage of the pigtail cables is that they use a single 8-pin on the PSU, and it’s only one cable.
The main disadvantage is that this single cable has to provide all the power required by the GPU, which means it will be carrying all the current and will get hotter. This reduces the longevity of the cable and could become a fire hazard depending on the quality of the components.
Running 2 cables in parallel means each cable carries one half of the current, which should be safer.
In reality whether any of this will become a problem depends on all the parts involved, but if you have the option, 2 cables is always going to be safer.
I think it’s ok if it’s 2x8 pin from the PSU, dangling 6 pin is not an issue
When a card needs two connectors you should always use two separate cables for each. The pigtails are when you use two cards.
So for the past 9 years I’ve been using the 8pin (from PSU) to 8pin + 6pin (to graphics card) this was wrong?
No it’s not wrong to use a single cable, it’s just not ideal. Depending on the quality of the cable and the connectors it may help a bit. 2 cables will always have lower resistance than a single one.
