Apple failed to officially announce the memory bandwidth with the M1, but claims the M1 Max is "just about 6x the memory bandwidth of M1." This, in principle, puts the M1 at close to 66GB/s of peak memory bandwidth. Taking a look at the details would not simplify the discrepancies. https://arthurotvlp.rimmablog.com/27771288/what-does-ajm1max-mean