Strange boot issue

[BinaryShadow]

I built my system a while ago, custom water cooled AM4 platform. It was working perfectly, I changed out the CPU waterblock and swapped to vertical mount GPU then the problem began, from 'cold' it will throw POST errors and hang, pressing restart over and over it will hang further and further into the POST until it does eventually boot. Once its booted up you can shut down and restart without issue. Next day after its been off for hours I have to go through the same process to get it to boot.

 

I have just reseated the CPU and its waterblock but this has not helped, any ideas? I have never come across anything like it! Have already reseated the RAM and tried with the PCIe extension unplugged, behaves the same way.

[Blasty Blosty]

Have you tried resetting the CMOS?

[BinaryShadow]

2 minutes ago, Blasty Blosty said:

Have you tried resetting the CMOS?

Multiple times

[Robchil]

inspect the PCIE slot on the GPU and the motherboard if anything are off in either. 

 

[BinaryShadow]

9 hours ago, Robchil said:

inspect the PCIE slot on the GPU and the motherboard if anything are off in either. 

 

Cant see anything wrong in either of the slots or on the connectors

 

I stripped the system out of the case a rebuilt on a table, left it overnight and tried it this morning, cant recreate the issue now. I'll build it back into the case and see if it does it again, could just be a mystery at this point.

[Robchil]

booting once without the GPU's in can reset UEFI in the bios and cause it to work too.