4090 kind of crashes the apple gpu, both in 3D rendering and LLM processing (except apple's MLX).
M4 Ultra is supposed to marginally beat 4090, but at that time 5090 will be here too, and if the difference will be the same as 3090-4090, it will have double the performance of 4090 in LLM, and at least 150% in 3D.
Also Apple claims are not entirely true.
https://www.youtube.com/watch?v=fdvzQAWXU7A