Adding to the clock throttling problem, it persists in 19.9.2
I think it is related to GPGPU activity. Thus far I've experienced the problem in:
Geekbench 5 (Vulkan or OpenCL)
Blender Benchmark (GPU)
Dragon Quest XI (not sure why it's happening here, but cape/clothing physics stuff may be offloaded to GPU)
Under older driver revisions, such as when I had my launch card in February, it was the RAM that would downclock to 800 MHz in GPGPU scenarios. Now it's the GPU that downclocks. RAM does not. You can never tell when this is going to happen.
I'm also wondering if some later driver revisions have stability problems at high OCs but that may be a separate issue.
I am going to report my card's problem. Thanks for the link.
edit: agh 19.9.2 is even worse, now I get the downclocking in Superposition! I've never had this before. It does it on its own, even when I do not have the bug kick in during a GPGPU benchmark beforehand. I might have to file another report with AMD, it's worse than I thought.