ASUS X399 Strix immediately shuts off if 8 pin 12V CPU power connected. Help?

[Zinn]

I just put this together so I've never seen as much as a BIOS screen, but it's a weird issue.

When I finished building and hit the power switch, the machine enters this infinite loop where it powers on, powers off a second later, waits a few seconds, powers on, powers off, etc.

So I tried to isolate the problem, I removed the GPU, front panel USB, memory, etc. same deal. So right now it's just a bare board with CPU, and no memory.

Finally I realized that if the 8 pin CPU power is unplugged from my PSU (Corsair RM750i) the machine powers on and stays on, but obviously the CPU doesn't initialize and the motherboard does not try to boot. When the 8 pin CPU power is reconnected, it goes back to the infinite fail state.

I know the PSU is good because I was using it for a month or so in my Intel build, so it seems like this is down to the motherboard or the CPU itself, but I'm not sure if I'm possibly missing something.

Did I get a DOA board, or is there something else I can try? Thanks in advance for any advice!

 

[Spartacus]

Are you connecting a PCI-E power plug (for GPU) by mistake instead of the CPU power plug?

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[Zinn]

Are you connecting a PCI-E power plug (for GPU) by mistake instead of the CPU power plug?

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Good question, and yes - I'm plugging in the dedicated 8 pin EPS cable to the correct spot on my PSU.

 

[LigTasm]

Since bad chips are unlikely, either you have a bad board or you messed up that six acre socket when you did the install.

 

[Nobu]

Sounds like it could be the memory or cpu (either bad, not seated properly, or bent pins) if it's not a power issue. Are there any debug leds on the board?

 

[Zinn]

Update: it was a DOA board. Swapped it with an MSI X399 Gaming Pro Carbon and the system is booting just fine. That's what I get for buying the first production run of an ASUS board

 

[OSEProphecy]

Update: it was a DOA board. Swapped it with an MSI X399 Gaming Pro Carbon and the system is booting just fine. That's what I get for buying the first production run of an ASUS board

I just had the EXACT same thing happen and I also went with the MSI X399 Gaming Pro Carbon as a replacement. The MSI came right up and has been flawless.

 

[Zinn]

I just had the EXACT same thing happen and I also went with the MSI X399 Gaming Pro Carbon as a replacement. The MSI came right up and has been flawless.

Yeah good choice, I love this board