Question Z790 steel legend wifi 13900k power cable / mobo issue

Sep 17, 2024
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I have been told previously that there’s no real need to use both 8-pin power connectors for a 13900k unless you plan on overclocking. So I’ve used it for about a year and a half now with only one 8 pin connector, but tried using two yesterday after doing some cable management and cleaning. When I turned the PC on the first time, it booted like normal, but I could tell something wasn’t right. I started downloading ICUE for my CPU cooler and when dragging the task manager window around it wasn’t smooth like it should be.

The ICUE install reached 100% and prompted me to restart, so I did. The PC turned on, but nothing happened on screen. It would cycle like 3 times then stay off. So l, being as frustrated as I was, I tried a couple more times since it clearly worked once (probably not a great idea) and nothing. So I unplugged the second cable from my PSU and it works fine. Why would it work with only one cable and not two? I’d like to use both if possible for cleaner power.
 
second power connector wont give you cleaner power, its there when you want to push your cpu above 300watts

as for the why it breaks when connected...bad psu or bad cable
The PSU i have is a EVGA gold 850w. That should be enough for a 13900 and a 3080 right? If not maybe it’s time to upgrade