EVGA G2 550w PCIE cable with 6pin AND 6+2 on same cable for R9 390?

[subtraction]

Sorry if the title is kind of confusing but here is the situation. I have never before seen a cable like this before but my recently purchased EVGA g2 550w pus came with a vga cable that has both a 6pin and a 6+2pin picee power connector on one single cable. Jonnyguru's review of the unit has a picture and describes exactly what I am talking about you can see it about two thirds of the way down the page here...

http://www.jonnyguru.com/modules.php?name=NDReviews&op=Story2&reid=440

My question is... Can I use this one single cable to power an R9 390 that requires both a 6 and 8 pin pcie power? Would it provide enough juice for this gpu or do I need to use the second pci-e cable came with the power supply which is a 6+2. I hope it makes sense what I am trying to explain and I would really appreciate any help that can be given.

It may seem silly but id really like to use just the single cable. Then I would not have an additional power cable running around my case. Especially since one of them will have an additional connector just dangling off of it being useless.

Thanks!

 

[lehtv]

Yes. The reason there are two connectors in one cable is so that you can use two connectors... and only one cable. If it was safe to use only one connector per cable, then there would be only one connector per cable.

 

[subtraction]

Thanks for the reply lehtv!

Sorry I knew it might have been a kind of silly question but... I have never seen anything like this before and wasn't sure exactly how it was intended to be used?
I just was unsure if they intended it to be used. I was scratching my head wondering why they wouldn't just include two 6+2pin connectors on separate cables. But I guess thats smart on their part and it'll keep me from only having to use a single cable!

 

[lehtv]

It's probably cheaper to make a cable with two PCIe connectors than two cables with one each, because the cable itself uses less materials, and you also need fewer connectors on the power supply's modular daughterboard. And it's more user friendly too - a single cable is easier to route through the case.

But I guess thats smart on their part and it'll keep me from only having to use a single cable!

Don't you mean it'll keep you from having to use two cables?

 

[subtraction]

It's probably cheaper to make a cable with two PCIe connectors than two cables with one each, because the cable itself uses less materials, and you also need fewer connectors on the power supply's modular daughterboard. And it's more user friendly too - a single cable is easier to route through the case.



Don't you mean it'll keep you from having to use two cables?

Haha yeah that's what I meant. Thanks again for the help. I guess I just wasn't sure if the single modular plug on psu would be enough to feed both pcie power plugs at once.

 

[Techhog]

It's probably cheaper to make a cable with two PCIe connectors than two cables with one each, because the cable itself uses less materials, and you also need fewer connectors on the power supply's modular daughterboard. And it's more user friendly too - a single cable is easier to route through the case.

Considering the fact that it also comes with a single 6+2 cable, it's most likely the latter.

 

[lehtv]

@Techhog
They are not mutually exclusive reasons. As I see it, the options are:
two cables - one 8-pin, one 2x8-pin
-OR-
three 8-pin cables

The first option is (presumably) cheaper to make, and reduces cable clutter for dual connector cards.

 

[MrTeal]

It's also (IMO) more estetically pleasing to have a single connector cable running to your card if you have one that is a single 6 or 8 pin connector.

As people have said, using a 2 connector cable is usually fine as long as you stay within spec. The one caveat to that especially with modular cables is that the current through both the 6 pin and the 8 pin would be running through one connector where that cable plugs into the PSU. If you plan on overclocking that 390 it could pull 400W, or 33A though that one connector. Since there's only three 12V pins, that's overspec for the Minifit Jr. pin.

I'd run two cables myself as I've melted them in the past, but that's in a high current 24/7 environment. Gaming should be okay, though if you don't mind two cables it wouldn't be a bad idea.

 

[subtraction]

It's also (IMO) more estetically pleasing to have a single connector cable running to your card if you have one that is a single 6 or 8 pin connector.

As people have said, using a 2 connector cable is usually fine as long as you stay within spec. The one caveat to that especially with modular cables is that the current through both the 6 pin and the 8 pin would be running through one connector where that cable plugs into the PSU. If you plan on overclocking that 390 it could pull 400W, or 33A though that one connector. Since there's only three 12V pins, that's overspec for the Minifit Jr. pin.

I'd run two cables myself as I've melted them in the past, but that's in a high current 24/7 environment. Gaming should be okay, though if you don't mind two cables it wouldn't be a bad idea.

Okay you got exactly what my concern was. I just wasn't sure how to put it into words. And yes I did plan on trying for a mild overclock. My only other hardware is an i5 6500, 1 ssd, mouse+keyboard, and the motherboard. Should I be okay just using the single cable?

 

[MrTeal]

Okay you got exactly what my concern was. I just wasn't sure how to put it into words. And yes I did plan on trying for a mild overclock. My only other hardware is an i5 6500, 1 ssd, mouse+keyboard, and the motherboard. Should I be okay just using the single cable?

I would use two myself, since you don't have need of the other one for anything else. In typical gaming usage you'll probably never have a consistent enough load to really heat up the connector, but it doesn't hurt to halve the current in each conductor. The only real downside is having to run an extra cable, and the visual of having that extra connector hanging around near your card.