@psvedas @liquidstudio @stargeizer
You shouldn’t suppose to change tile size in 3.0. Tiles were repurposed to render very high-res images like 4k,8k or 16k and bigger. They aren’t used for performance tuning anymore. You can leave tile size at 2048. In new Cycles all devices are cooperating on one tile. Basically unless you are doing hi-res images you can forget about them.
You can report bad performance with AMD GPU+CPU rendering as a regression. I suppose it wasn’t tested well.