Correct power cable for my MSI GTX 970 4GB graphics card?

[jedi55]

Hi,

I recently purchased a MSI GTX 970 4GB graphics card, it has two power connector sockets, an 8 pin and a 6 pin.

I also have a Seasonic X650 650W 80+ Gold Certified Full Modular PSU which came with a black cable (part no. CG04) that has an 8 pin connector labelled PSU at one end that goes into my PSU.

At the other end the cable has an 6/8pin connector which then has a short cable coming off it to another 6/8pin connector both labelled PCI-E.

Is it safe plugging both ends labelled PCI-E into my single graphics card and plugging the other end into my PSU?

Any advice would be greatly appreciated
Thanks

[Abula]

The X650 is fully modular, should come with single 8pin PCIe GPU cables to 8pin PSU connector cables, some of the seasnoics come with this cables and has an extra 6+2 in the same line, this should still be good enough to power any card, i personally use single lines to have better distribution on the load, even when its a single 12V rail, i prefer to have single cables directly, meaning i send two of those to each gpu, in my case my GTX970 only use a single 8pin, but if i were to have two connectors again, i would send individual lines to each gpu to each connector.

Now this is more a preference, and the GTX970 is a very efficient card, as i said asus runs it on a single 8pin and works fine, even overclocking, but other manufacturers have opted for 6+6 or 8+6.... a lot of people like to overvolt to get high overclocks, something i do not do anymore, but it should be fine even with a single cables, as the card doesn't as for much, but in case you overclock heavy, and want to have as much power available, run dual lanes.

[jedi55]

OK, now I'm confused.
I just got back 2 e-mails, one from MSI one from Seasonic, both contradicting one another!
Which one should I listen to?


Dear James,
Thanks for contacting MSI technical support team.
It is safe. However, please make sure both the 6pin and 8pin are plugged into the graphics card.

Thanks and Best Regards,
MSI Technical Support Team


Hi James,
Thank you for purchasing Seasonic!

It is best to use 2x separate PCIe cables for your GTX970.
Each cable providing power to each single PCIe power connector.

If you use a low power consumption VGA, then you can use the 2x PCIe connectors on the single PCIe.

Regards,
Walter

[Cistron]

Whether it is safe will have to do with the cross-section of the wires used. I'm pretty sure they will be over-dimensioned and you'll be fine.

If you follow Abula's reasoning, many GTX970's need only a single 8-pin plug. That would imply the amperage poses no problems for the cable. In your scenario, all that changes is an extra split and plug.

[quest_for_silence]

Which one should I listen to?

MSI: did that Seasonic rep write anything meaningful, according to you? "If you use a low power consumption VGA, then you can use the 2x PCIe connectors on the single PCIe.": mind, do you know *any low power consumption VGA" which actually needs two PCIe connectors? I don't.

[jedi55]

I've found the Seasonic rep to be vague and at times patronising. The MSI rep is also vague but more helpful.

I've added photo to help clears things up.

Thanks

[Vicotnik]

With the X650 you should have gotten two such cables I think. I would use them both but using a single cable should also be fine.

[quest_for_silence]

With the X650 you should have gotten two such cables I think.

Yes, they are two: if the OP lost that cable, in North America can order it to Seasonic USA (or a distributor), in EU he should order the whole set (although it's relatively cheap, about 20 bucks).

using a single cable should also be fine.

I do not say "should also be", Vicotnik, but "is".

To the OP: the cable itself must handle a *minimum* of 150W and Seasonic cable gauge is conservative, the PSU itself is single rail (54A/648W at GPU's beck and call, no current protection), the PCIe slot supplies 75W on its own, the card will peak around 190w while gaming and around 210W stressing with FurMark, overclocking it to more than 1540Mhz (Boost) adds about 25W of further draw, so there is no issue running the card off a single cable.

[Vicotnik]

But think about the wasted heat in the cable. Gotta save those small pieces of Watts, they add up.

[jedi55]

Hi,
I don't intend on overclocking
Thanks

[quest_for_silence]

Hi,
I don't intend on overclocking

It doesn't matter, as it's fine whether you'll o'c or not.

[quest_for_silence]

But think about the wasted heat in the cable.

Just for (our) information, Vicotnik: I did just a quick search, and apparently each 12V wire (there are three) in that Seasonic cable can carry up to 16A, practically limited by the specific connector pin quality (unknown to me) to about 8A (min) - 11A (max).
Then, still apparently, that single PEG cable should be able to handle from 24A (~290W) to 33A (~400W), so far more than needed by any GTX-970, and at least two times how much an 8 pin PCIe connector is rated.
Obviously feel free to correct me if you think I'm wrong on something.

[Vicotnik]

Sure, the reason for two cables is for setups with two graphics cards. One cable per card. I'm just saying that I would probably use them both for a single card unless that would look funny or mess with cable management. On pure principle since twice the cabling is half the resistance. So it's not a technical point from my part, more like a religious one.