Have you tried using an older LTS kernel, such as linux612, linux66 or even linux61? New kernels aren’t always the best choice for an older machine. You may find that the older inbuilt AMD GPU drivers provided with older kernels work better with your hardware.
If an older kernel does not fix the issue, then more information may be required for troubleshooting. Please read through the following pre-prepared instructions and provide the requested info (the output of inxi -zv8) so that others here may be able to provide assistance:
As a new or infrequent forum user, you are encouraged to take some time to familiarise yourself with Forum requirements; in particular, the many ways to use the forum to your benefit:
The Update Announcements contain a Known Issues and Solutions section and should generally be checked before posting a request for support.
Output of the inxi command (with appropriate parameters, and formatted according to forum guidelines) will generate information useful for those wishing to help:
inxi --filter --verbosity=8
or the short form (preferred):
inxi -zv8
- inxi man pages (Arch Manual)
Regards.