The problem is, I have a rig on MB Asrock H110 Pro BTC+ and VC 8x XFX RX580 8G, after rebooting rig (for power issue or just reboot from windows) in case of 50/50, it's randomly happening, one of cards is not defined, just disappears from system, it's can be any of eight cards, so problem is not in cards or risers, maybe prolem is in MB. After the start of all eight cards, rig works stable for many days.
Check the bios for a delay in boot time. I have some boards that let me set up to several seconds delay before boot. Ive always used the longest delay to allow the pcie bus to read all cards on my 13 gpu rigs. Hope it helps you.
I tried many of things, but it's a good idea, I remember that a few years ago disable fullscreen logo and set delay on 3sec, I will try to increase delay, thanks
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I'm not aware of any BIOS boot delay, just the bootloader which has nothing to do with HW detection.
I think there's a problem that requires troubleshooting. The problm is intermittent and affects GPUs randomly, the most difficult to solve.
My first suspicion is the PSU. If you have a spare, preferable a bigger one, give it a try. If not try removing one GPU to reduce power and see if
the problem goes away. If it's not a power issue then you're looking at a possible BIOS/motherboard issue. Updating the BIOS may help.
Shuffling slots and risers can also help make problems mysteriously disappear, sometimes a shuffle just reveals a pattern that leads in one
direction.
Regardless a better workaround would be to count the GPUs after reboot instead of relying on hashrate to detect a missing GPU. There are many
ways to do it from a command line or BAT file