AMD's software has always been in a very sorry state. Only after non-inhouse developers created an alternative GPU driver from scratch for Linux it became feasible to use.
AMD patches for preferred core (prefer those cores which can clock higher) are a mess and ended up not working because of a wrong if condition. Showing that no one at AMD even tested it before submitting. The programmer in the video complains about AMDs developers being incompetent and shows how it's fixed.
Apparently there's a bug in an AMD's driver. It was supposed to assign processes based on each core's self reported performance, but because of the bug it was random.
This "self reported performance" is based on evaluation done to the cores in the fab process, by AMD. Meaning, due to imperfections some cores are a bit better than others.