Supermicro X11DPH-T 3x 8-Pin Power?

[System48]

I'm looking at getting the X11DPH-T motherboard and it has 3x 8 PIN power connectors and the motherboard manual doesn't indicate you're ok without having all three connected. The product page specifies several chassis that have power distributors that only have 2x 8 PIN connectors, I'm specifically going to be using the 826 chassis. I'm assuming it will work fine with only two connected despite the manual not stating this?

 

[admin4fun]

I discovered the same issue, it isn't very clear at all. I cannot get the motherboard to power on, I've tried several configurations, 3x 4 pin in each 8 pin connector; 2x 8pin in two of the 8 pin near the CPU etc... the power supply clicks but never powers the board, as-if there is a short. The supply powers on via paper clip. Nothing else is connected, motherboard isn't even in a chassis, its sitting on glass. Obviously i have the 24 pin main power on albeit the plug is extremely stiff. I will try swapping CPU re-arranging & trying only CPU 1, to see if anything happens.

 

[admin4fun]

Well the manual states "You must also connect the 8-pin (JPWR1/JPWR2/JPWR4) power connectors to your power supply " and "PWR1, JPWR2 and JPWR4 are the 8-pin 12V DC power input for the CPU or alternative single power source for a special enclosure when the 24-pin ATX power is not in use" .... so this is ambiguous as hell.

 

[jerrytsao]

I found this out when this board first came online and shared the spec on CHH forum back in September last year Skylake-SP双路绝配之X11DPG-QT和X11DPH-T规格简析-Chiphell, some guy over there also had the same question so he contacted SM engineer and received the following:

The 3rd 8-pin is only necessary for 255W TDP CPUs, only 2 8-pins are needed for dual <205W CPUs

So this board is apparently made to be future-approved since Cascade Lake-SP will have 245W SKUs and currently there is a 3.7G LGA 3647 undergoing test according to AT's Ian Cutress on Twitter. For Skylake-SP, however, you don't need the extra 8-pin.

 

[Patrick]

@jerrytsao Ian is on vacation but I was chatting with him this morning. He got a kick out of the shout out.

 

[admin4fun]

Thanks jerrytsao! that's impressive detailed information! I'm running dual Xeon 8160, and I wasn't reaally thinking the 8-pin connectors were the issue, but helps for trouble shooting. Power supply clicks but never powers on seems to indicate something wrong with the connection/ground I would assume. There is nothing, connected to it; just 1 cpu; 1 stick of memory (not even cpu fan for the moment, which is also extremely ambiguous in the documentation ). I think the motherboard might be bad, suspect is the main 24-pin connector -.- unless anyone else can think why this might occur. I would assume missing/wrong memory would power up then beep etc..

 

[AJXCR]

Just an FYI- my X11DPH-T works perfectly with dual 165W 28 core processors installed and only two 8-pin connectors (1 & 2) in use.

Ultimately, I repurposed 4x 12V & 4x gnd wires from PCIe connectors to the appropriate 8-molex connector for the third board connection, but this had no noticeable impact on performance.

 

[admin4fun]

Well I'm a jackass, the memory I was using was not ECC. This is embarrassing. I miss read the website as supporting multiple memory types including non-ecc. So I will amazon prime the correct memory.