Filipe Esposito at 9 to 5 first reported on this, from a test by Andy Somerfield at Affinity Photohttps://9to5mac.com/2021/10/25/apple-m1-max-gpu-beats-6000-amd-radeon-pro-w6900x-in-affinity-benchmark/
This is pretty amazing, beating a $6000 GPU from the 2019 MacPro! Wow. So the Apple Silicon iMac Pro and Mac Pro will certainly be impressive machines.