Well I wouldn’t say it sucks, obviously it’s not competitive with the new generation gpu but trust me it’s still a nice gpu.
This is an old video from 2018 or 2019, which I used to report some bugs to the blender developers.
As you can see, EEVEE realtime rendering, is obviously not performing in realtime, but it allows a complete rendering in OpenGL, moreover, by deactivating the advanced shading it has excellent performances that allow modeling or other in blender, even with meshes with a consistent polygonal density.
I know for direct information, that these gpus on linux have the same R600 Gallium driver, covering 10 years of gpu, from 2006 radeon HD 2000 to 2016 radeon HD 8000 if I’m not mistaken, so anyway with one driver you cover a lot of gpu .
Games of the caliber of The Whitcher were running on this gpu, which is no small feat.
Anyway we were talking about the potential support of old GPUs that only have OpenGL, I just pointed out, that by supporting Mantle, Vulkan could potentially approach these GPUs as well.