Single or dual 8-pin

[Freyeth]

Hello.
Can You please help me with an issue?
I plan changing Motherboard and CPU for 7800X3D and ASUS X670E-PLUS GAMING. Thr motherboard has two 8-pin CPU power plugs, while my PSU (850W) has only one cable of that kind. It is said nowhere in the manual of the MoBo that both are or are not required for it to work. What is the truth in that case?

 

[Deleted member 229121]

It's only a 120W chip, you're totally fine with using 1x 8-pin.

 

[Freyeth]

The problem is that tech support from Polish ASUS (I'm from Poland) website told me that both are needed for MoBo to run as specified in the manual....which is not mentioned anywhere. It isnonly said to be sure 8-pin plug OR both 8-pin plugs are connected.

 

[Deleted member 229121]

It's only necessary if the CPU draws enough power to warrant it, you are fine.
That rep either didn't know, or they just say that to cover their butts in general.

 

[Gmr_Chick]

The problem is that tech support from Polish ASUS (I'm from Poland) website told me that both are needed for MoBo to run as specified in the manual....which is not mentioned anywhere. It isnonly said to be sure 8-pin plug OR both 8-pin plugs are connected.

In general, only ONE 8-pin EPS cable is actually REQUIRED to be plugged in + the 24-pin for the system to work without an issue. In most cases, the 2nd EPS header that you see on mobos nowdays is really only there to provide extra power when doing serious OCing.

So the TLDR is that you only need to plug in one 8 pin EPS cable. The 2nd one is (mostly) for show.

 

[Freyeth]

Thanks for a swift and precise answer

 

[DemonicRyzen666]

It's nice to have both connected for overclocking but unnecessary for every day normal task.

 

[Assimilator]

The problem is that tech support from Polish ASUS (I'm from Poland) website told me that both are needed for MoBo to run as specified in the manual....which is not mentioned anywhere. It isnonly said to be sure 8-pin plug OR both 8-pin plugs are connected.

That tech support doesn't know jack s**t.

 

[GerKNG]

there is no CPU that you can put in that socket that can saturate a single 8 Pin. (336W)

 

[ir_cow]

Only need one. I do it all the time. Plus single 8pin EPS cable can do 300+ watts

 

[P4-630]

I use both for my i7 12700K, just because I had them.

 

[Freyeth]

One more question: are you answers given from theoretical or practical experience?

 

[Ferrum Master]

That tech support doesn't know jack s**t.

I can double on that.

 

[TheLostSwede]

I can give you the answer from people I know at Gigabyte, only one is needed. The second one is only needed for extreme overclocking.
Also, I have been running with one in my past two setups without any issues.

 

[Ferrum Master]

On serious note.

There is only one more thing. The ground plane and shortest return path. On some poor motherboard designs, where the layout is done by monkeys... you can have some anomalies, like VRM NOISE, NOISE in speakers from integrated sound etc. Adding additional plug my steer the return path from ATX24pin connector for example etc. You may break the loop.

But those are esoteric problems.

 

[GerKNG]

are you answers given from theoretical or practical experience?

both.
i ran GPUs and CPUs on tons of different PSUs far beyond 300W per 8 Pin and NEVER had an issue.

 

[Freyeth]

That is what I thought the same. I asked the polish ASUS tech support to give me a precise answer and yet again they used the words "according to the manual" which is a common b******t used by undereducated support workers