only adapter to trust if that is 2x molex to 6 pin. I wouldn't even use that. To clarify all your risers are powered and if so how so please?

hermes980
I have PCI-E Risers and multiple GPUs. I want to power all of these direct from the PSU without adapters.

I have wondered about using 2 6 pin power connectors on the riders i'm sure it's fine,

I have done a ton of research and in my scenario I can only fit one PSU in my 4U server (the third post is mine).

Thank you for the recommendation on the dual supplies (I had already looked at those and was concerned about consistent power/allocation).

My goal is a single PSU and do not require to be “spoon fed”. While I understand your frustration (and I did search/research but nothing exactly matched my scenario), your frustrations could be better stated.

I did read them and none of them spoke to using the 6 +8(6+2) cable to power two risers

If you have the leads and they don't reach, fifty bit some cable extenders.

Power Splitters are Known to cause Graphics Card Failures.

Extensions to existing cables should be fine. They don't add any connections so there would be no issues. I do recommend buying from a reputable source and not eBay and the like.
Splitters which add connectors are bad as they can easily trigger your power supplies ocp (causing unexpected shutdown) or cause a fire if the words in the cables are too thin a gauge.

Tldr: quality extensions are good. Splitters are always a bad day waiting to happen.

I bought one from Amazon made by Cable Matters. It extended my atx cable. But Silverstone (case maker) and cablemod make them as well.

hermes980
I did read them and none of them spoke to using the 6 +8(6+2) cable to power two risers

Yes, you CAN do so - but it's a waste as risers can be SAFELY powered via MOLEX with no "extenders" needed.
EVGA "perip/sata" ports will easily and safely handle ONE riser per port.
 
https://www.newegg.com/Product/Product.aspx?Item=N82E16812423198&ignorebbr=1 is my "go-to" riser, but there are lots of other options for MOLEX power to a riser.
 
If you already have PCI-E powered risers, they can also be safely powered via an adapter from a MOLEX to the PCI-E 6-pin connector (one MOLEX is plenty, though 2 doesn't HURT if you already have "dual molex to PCI-E 6-pin" adapters on hand).
 

Basic rules for extensions: You have to understand only the minimal amount of electronic principal to understand the safe way to add an extension. Electricity, aka electrons, flows through the wire. The wire offers resistance to the electrons. Resistance creates heat. So if you want to add an extension, you need to make sure the wire gauge, aka thickness of the copper, offers the least amount of resistance. With that in mind, you need to use the same gauge or larger for your extension. (Larger gauge wire has a smaller number. 10 gauge is much larger than 20 gauge.) Also, keep with the shortest extension you can use. The length of the wire will also increase the resistance, but this should be negligible with such short extensions.
 
Splitting the power between 2 loads is essentially creating a parallel circuit. By splitting the power, you create a situation where each branch is only receiving half of the current it is designed to receive, which will either suffocate the end devices for power or create an over current situation for the source. Either can result in an undesirable condition. Only use splitters if your power supply was designed for them.
 
But why can I plug multiple things in my house plug?  These circuits are designed with parallel usage expected. That is why your plug (USA 120v) usually uses a 20 amp breaker. Many household items (other then motors) draw minimal amps. The circuits are usually designed for 80% utilization. This is why too many extension splitters can cause a fire.
 
Regards . . .

Yes, voltage stays the same on a parallel circuit. I said power, meaning amperage, is split. I guess I should have said current. This is simple Ohms law stuff. What I said is absolutely correct. If Source "a" provides lets say 3 amps, and it is designed for destination "b" which draws 2 amps, then plugging in 2 destination "b's" would result in both destinations being a half amp short or over taxing Source "a" causing it to try to produce more amperage then it is designed for. The only way you can safely split in my example is if each destination only draws 1 amp for a total of 2 amps which would still be below the 3 amps produced. Keep in mind that you need to maintain a margin of free amperage to compensate for inrush.
 

Adding an equal parallel load, doubles the current draw at the source. This doesn't even take into account all the additional legs of the circuitry. If this 5 amp circuit is given an additional equal load, the current draw is split. This goes above the designed 5 amp circuit. As a higher current causes additional heat, it increases the resistance and causes a drop in voltage. This has the net effect of decreasing the amperage to each end device. I feel like I'm speaking a different language here. Are you trying to say that splitting and adding an additional load is safe? Because it is clearly not.
 
Edit: Ok I went back and looked an my original post. It was misspoken, but the principal remains. Splitting is bad.