Try disabling fast start. Read this please > The Pros and Cons of Windows 10’s “Fast Startup” Mode
Deciding whether to bother with Fast Startup actually takes longer than turning it on or off. First, open up your power options by hitting Windows+X or right-clicking your Start menu and selecting Power Options. In the Power Options window, click “Choose what the power buttons do.”
If this is the first time you’ve messed with these settings, you’ll need click “Change settings that are currently unavailable” to make the Fast Startup option available for configuration.
Scroll to the bottom of the window and you should see “Turn on fast startup (recommended),” along with other shutdown settings. Just use the check box to enable or disable Fast Startup. Save your changes and shut down your system to test it out.
If you don’t see the option at all, it means hibernation is not enabled on your machine. In this case, the only shutdown options you’ll see are Sleep and Lock. The quickest way to enable hibernation is to close the power settings window and then hit Windows+X and open Command Prompt (Admin). At the Command Prompt, type the command:
powercfg /hibernate on
After turning hibernate on, run through the steps again and you should see both the Hibernate and Fast Startup options.
I too have problems with resume from standby with the latest drivers installed: 19.4.1.
Following your advice I updated the chipset (B450) drivers from the Asus website and then updated later with the new version available on the AMD website: 18.50.0422.
I then re-flash the bios with the V1002 and loaded the default parameters, started windows and everything ok: PC goes on standby and wakes up correctly !!
I then returned to the bios to start setting my parameters, which have always worked with the my previous video drivers (19.2.3).
Meanwhile I activated the profile D.O.C.P. #1 to work at 3200MHz with my ram (as I have always done), I saved and restarted and... the PC goes into standby, but does not wake up properly..
I returned to the bios to cancel the DOCP #1 profile, but nothing to do: the PC never wakes up correctly from standby..
I tried to re-flash the bios again with the exact same version 1002, default parameters and.. so it works.. but, as soon as I set my profile DOCP #1 there is no more towards: something gets dirty..
All this makes me think that the standby function is currently very fragile on AMD.
My system spec:
CPU & GPU: Ryzen5 2400G
MB: Asus b450M-A
RAM: 16GB DDR4 3200MHz HyperX HX432C16PB3K2/16
I had a same issue with monitor sleeping. (Gigabyte AB350M-HD3 and Ryzen 2400G). I tried every bios with every vga driver, and only one worked: 2019/09/25 vga driver with any bios. But this driver had another problem, the embed video reloading with green tint. It was repaired by AMD at the end of 2018 or early 2019.
My solution is: changing the cable. I connected the monitor with a dvi-d cable, and the sleeping problem has gone. I can use the fresh vga drivers. The previous hdmi cable is working fine in another computer :-)
Might early to say, but after updating windows 1903, my monitor is waking up ok, windows 1903 installed Microsoft driver 220.127.116.11.2003, it worked ok. Now I updated to AMD 19.6.1(26.20.11015.9003), still waking up ok. Fingers crossed...
Im sorry, my answer related to zemuan's 2.nd issue, when the monitor in stand by mode gone black, but the backlight wont turn off. I tried to find solution (clean windows install with windows 10 1809/1903, different bios and vga drivers), the cable changing was the key.
thats the solution for this problem!
I connected my monitor with a displayport cable and now everything is working fine!
It seems to be a HDMI driver problem.. I read somewhere the HDMI audio channel stays active when going into standby mode, what leads to this problem.
thank you very much!
With 19.6.2 problem came back again. Using 2 monitors on vga and dvi port, dvi no problem, vga stays black after about 10min of standby. At least now I have newer driver 19.6.1 that I can live with, a big jump from 18.9.3.