Question Strange boot behaviour- posting but no windows on cold boot

[MEMOFLEX]

Afternoon all. Hoping for a bit of help if possible on a bit of a head scratcher.

Long story short - built a new system for my neighbour. During regular use it is rock solid with no crashes or anomalies. On cold boot however the system posts but the monitor screens then go black as if they lost connection. This is consistent 99% of the time with the very rare occurrence where the system does go straight into windows. If the system is restarted the system goes straight into windows.

The system:
CPU : 9800X3D
Motherboard : MSI MPG X870E
Ram : 32gb (2x16gb) Corsair 6000 C30
CPU Cooler : CORSAIR LINK 360 TITAN AIO
SSD 1 : Corsair P310 1TB NVME
SSD 2 : Corsair P310 2TB NVME
GPU : 4070ti super
PSU : Corsair RM1000X SHIFT
Case : Hyte Y70
Fans : 6 x Corsair Link RX120 RGB
Monitors : 2 x Samsung G5 CURVED 27"

Now I have tried what I believe is everything I can think of to try and fix this with the key bits below :

Motherboard BIOS updated to latest release
Full windows reinstall with redownloaded image and multiple different usb sticks
Switched RAM, GPU, SSD position
Booted with single stick of RAM with and without XMP enabled

As i have switched out most components with my own (virtually identical system apart from GPU) at i a little stumped.

Now I can get it to cold boot without this issue by using my portable monitor and HDMI and so far it has booted first time everytime today. I have cold booted 20+ times without any issue whatsoever. Can this be related to the screens?

The screens are connected via display port (2.1 cables but same issue persisted with 2 different known working cables which I think were DP 1.4). The screens have also been tried with hdmi and we had the same boot issue however.

Could this be a screen firmware issue? Anyone had anything similar to this?

As mentioned the system is fully functional and performs well once into windows so this is more of an annoyance than anything but finding a resolution would be amazing.

 

[rgd1101]

turn off fast boot in bios?

 

[MEMOFLEX]

turn off fast boot in bios?

I am sure i have tried this already but I will double check and report back

 

[Ralston18]

And I will add the suggestion to power down, unplug, and open the case.

Verify by sight and feel that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place.

New build: no one wants to force anything with a new build so what feels to be in place may not actually be so.

The described behavior appears to me that some connection is not fully secure and requires a bit of warming to expand and tighten up. Maybe just a bit of vibration or other movement.

To be more specific: just unplug and replug everything a few times.

Do leave the CPU alone.

You may discover that something suddenly goes into place much more smoothly and feels more secure.

And, hopefully, all will be well.

 

[MEMOFLEX]

And I will add the suggestion to power down, unplug, and open the case.

Verify by sight and feel that all connectors, cards, RAM, jumpers, and case connections are fully and firmly in place.

New build: no one wants to force anything with a new build so what feels to be in place may not actually be so.

The described behavior appears to me that some connection is not fully secure and requires a bit of warming to expand and tighten up. Maybe just a bit of vibration or other movement.

To be more specific: just unplug and replug everything a few times.

Do leave the CPU alone.

You may discover that something suddenly goes into place much more smoothly and feels more secure.

And, hopefully, all will be well.

Thanks for the suggestion. I have double and triple checked connections and they are all fully inserted

I had a feeling it might be something like this initially due to the sporadic nature of the situation however it was not the root cause of the issue unfortunately.

We have tried on every bootup so far this week attached to a portable monitor and it has booted first go everytime so its a strange one. This is what is leading me towards the monitors being directly related - as a strange as this actually sounds and is not something I have come across in 20+ years of building PC's