-Download gpu z and check the driver power state it’s in well in game. In nvidia control panel if you have it set to prefer maximum performance the power state listed should be P0 or P2 anything higher then those up to P8 or higher is a power saving state for low preformance tasks and those tasks will keep it in a low Hz state. Make sure nvidia control panel is set to prefer maximum performance for the game itself not just global settings. You can also install nvidia inspector and get better control over the power states. Changes may require a reboot.

-Other things to check in game what happens when you use k boost in game. Does it max clock or not? (Not sure if you can on asus card)

-In game try running the game in disabled optimized fullscreen compatibility in the games main .exe properties.

-Does your computer have a APU? Make sure phsX is dedicated to your GPU card. If the game runs OpenGL or Vulcan make sure it’s set to your dedicated gpu card in nvidia control panel advanced settings.

-Optamus setting may also need to be setup using nvidia inspector to prevent the game from defaulting to the APU if you have one.

https://forums.geforce.co...-control-over-optimus/

-Disable windows 10 gamemode and game bar as it hooks full screen in some games which causes issues.

-Windows 10 setting - display - graphics settings - browse add game - options - high performance.

-Set your computer to high performance power settings. Search - control panel - power - high proformance profile.

-Check the gpuz pcie port gen and speed is it 2.0 x16 x8 or 3.0 x16 x8 when clicking render test.

I noticed your also running a windows 10 pro insiders build has this occurred in the main stable branches 1803 or 1809?

The reason I wanted him to change it was because some AMD Ryzen chips have APU’s built into it “cpu graphics” and if it defaults to cpu it may also default to the apu depending on if he’s using using the boards build in hdmi port opposed to the graphic cards HDMI port.

Low Hz clock could be because his dedicated gpu may be idle OSD or FRAPs could tell him which graphics device is in use by clock speed normally.

His Ryzen 5 1600 doesn’t have a APU after checking, but I’d recommend him plugging into the gpu’s HDMI port or display port opposed to the motherboards if it has one.

"I set the PCIe to 16x/8x and to Gen3. I also used auto."
In the Bios can you Force X16 and GEN3?
I wonder if this could be an issue with AM4 Chipset Software?
Is the Chipset Software current?

You should be able to find the correct vbios for your card here.