I've been struggling with this issue for months now, and I thought I was able to replicate it but I am not.
Every time I wake from sleep after several hours the computer wakes, but the screen is black. I can access the system remotely and the GPU is missing from the device manager and nothing will enable it other than multiple hard reboots.
Gigabyte 5600 XT 6 GB Gaming OC
ASrock B450 Pro 4 on 3.9 Bios
EVGA 650 GA PSU
Samsung 960 Pro SSD M.2
AOC G2590FX 1080p 144hz FreeSync Monitor
Troubleshooting Steps Done:
Flashed the GPU to the newest BIOS, did not help
Attempted to disable Ultra Low Power Standby in Registry
It did not have the entry, and adding it changed nothing, GPU-Z shows it as N/A
Disabled Hybrid Sleep
Reverted to first VBIOS version
Installed multiple versions of drivers after DDU reset
Updated Chipset Drivers
Completely reformatted and did a clean install of WIndows 10 on 2004
Reset MB Bios to default settings
Nothing seems to help. I can wake it if it's been less than 6-8 hours, and it comes up fine, if not kind of taking a bit longer than I would anticipate. Usually 10-15 seconds, but if its after several hours the fans will ramp up and nothing on the screen.
I can use Teamviewer or RDP to remote in, the machine is up and awake, but the GPU is gone. Nothing is listed at all in device manager. It's like the GPU didn't wake although the fans are on and the LED is on.