Strange cold start up behaviour on my HP Z800 workstation


New Member
Hi all,

Just looking for ideas here. I have a HP Z800 workstation computer with dual 3.06Ghz Xeon hexcore CPUs (24 threads) and 48Gb of ECC DDR3 RAM (triple channel 12x 4GB DIMMs) and a 4Gb Quadro K2200 GPU and a Samsung 1Tb 850 Pro SSD. It's not a recent computer, but it still performs well. But it has a problem. When the system is cold after it has been turned off overnight, for instance, the next time it is started it will suddenly turn off, usually during POST. It will then restart and attempt boot but turn off again. This will repeat with it sometimes getting to the Windows bootloader. If I jump into BIOS when it restarts and let it sit until the system temperature comes up to the high 30sC then exit it will usual boot fine. If the system is warmed up to this level it tends to behave normally. I have done the PSU self-test, but this comes back as OK. I have tried removing RAM sticks to see if its dodgy RAM, but these all come back OK too. Any ideas of what could be causing the issue? I suspect a component is failing when cold, but once warmed up operates Ok. Could this be on the motherboard itself? I'd love any thoughts from knowledgeable persons out there. Sudden power tripping does indicate PSU, but I can't find anything definitive anywhere. Someone somewhere must have had the same or a similar issue.