Their "peak GPU compute performance for AI" is quite different from your unqualified "performance". I don't know what figures they're quoting, but something stupid like supporting 4-bit floats while the predecessor only supported down to 16-bit floats could easily deliver "over 4x peak GPU compute performance for AI" (measured in FLOPS) without actually making the hardware significantly faster.
Did they claim 4x peak GPU compute going from the M3 to M4? Or M2 to M3? Can you link to these claims? Are you sure they weren't boasting about other metrics being improved by some multiplier? Not every metric is the same, and different metrics don't necessarily stack with each other.
Did they claim 4x peak GPU compute going from the M3 to M4? Or M2 to M3? Can you link to these claims? Are you sure they weren't boasting about other metrics being improved by some multiplier? Not every metric is the same, and different metrics don't necessarily stack with each other.