Not many codes are bandwidth bound, but you can't say without knowing the use case.

Another factor is mac's have many more memory channels on the m1/2/3 pro and m1/2/3 max. So they can have many more memory transactions, where on most PCs and x86-64 laptops you get 2 cache misses per memory latency (on the order of 70ns), where macs will get many more. So under various workloads all the cores spend much less time waiting on memory latency.