New intel i9 build, will not post.

[Pheryllt]

I recently bought an Intel I9 7900X along with the MSI X299 M7 ACK MB. In order to determine of the motherboard would post I installed the CPU, a compatible cooler, the RAM, and a graphics card. I plugged in the 8 pin for the GPU, the 24 Pin for the MB, and the 8 pin for the CPU. When I tried to power the system the MB flashes momentarily, not even long enough for the cpu fan to begin spinning and after a few seconds tries to power on again with the same result. In order to understand what was happening I removed the GPU, same outcome. However after removing the 8 Pin CPU power the MB starts up. Any ideas on what the problem could be? PSU? MB? CPU? hopefully its not the latter because it was an expensive miracle that I got my hands on that I9 to begin with. My biggest problem is since the socket and the cpu are so new its not like I have spare MB and CPU's that are compatible lying around to test them.

 

[kanewolf]

What about the 4 pin for the CPU? The documentation that is on-line is horrible, but I think you have to have both the 8 and 4 pin CPU power connected.

 

[mdd1963]

X299s have a pair of 4 pin inputs, I think? There are little adapter cables that split a single into a double, and some PSUs come with dual snap together 4 pins...