Re: Performance claims
Benchmarks of last year's M1 GPU by Anandtech:
https://www.anandtech.com/show/16252/mac-mini-apple-m1-tested/3
They found it to be the equal of a low-end discrete GPU but far more power efficient.
It should also be remembered that after the independant benchmarks of the M1 came in, Apple were seen to have been straight in their their presentation about the M1's performance.