Question Home-built system requires multiple powerups to boot after being disconnected from power, but then boots/operates normally afterwards


Apr 30, 2017
This is one of the strangest problems I've ever encountered.

A couple of weeks ago I built a new system with the following specs:

CORSAIR RMX Series, RM850x, 850 Watt Modular Power Supply

Gigabyte Z390 M Gaming (Intel LGA1151/Z390/Micro ATX/M.2/Realtek ALC892/Intel GbE LAN/HDMI/Gaming Motherboard)

NZXT H400i - MicroATX PC Gaming Case

CORSAIR Vengeance RGB PRO 16GB (2x8GB) DDR4 3000MHz C15 LED Desktop Memory

Intel i7 9700k Processor


Kraken x62 AIO Liquid Cooler

I have the computer in a home office, but I also have a roomscale VR setup in my living room, so I move the computer back-and-forth between the two rooms with some frequency. This obviously requires disconnecting the system from power in one room and reconnecting it in the other.

Whenever the system is disconnected and reconnected, it (usually) fails to boot when it's powered on. The RGB strips light up and the fans spin, but there's no beep code and the GPU fan slows to a stop after spinning up initially for about 5 seconds. It stays like this indefinitely until I hold the power button to shut it down.

The system seems to have about a 20% chance of powering up normally. Sometimes it happens on the first attempt. Sometimes I have to cycle it like 7 or 8 times. In any case, I eventually get lucky and the fans spin up, then slow down, then kind of lurch on to full speed. I get a reassuring single-beep POST code, and the system boots normally. After this occurs, the computer boots normally 100% of the time and operates perfectly until it's disconnected from power, and then I have to go through all the rigmarole I just described again. Even cutting and reconnecting the power through the power supply switch while leaving the cord where it is triggers this behavior.

I can't figure out what's causing this. It's kind of a minor annoyance in some ways, but it's also disconcerting (computers ought to boot normally on the first attempt every time) and I'd appreciate any help getting to the bottom of it. Thanks!
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