I’m guessing the performance improvements derive from integrating the memory onto the same chip (instead of using external memory), not from ARM (although power savings come from ARM). So we will probably see a new era of laptop SoCs, but that also means coupling RAM with CPU (or maybe you can mix and match the on-chip RAM with external RAM?).
“One aspect we’ve never really had the opportunity to test is exactly how good Apple’s cores are in terms of memory bandwidth. Inside of the M1, the results are ground-breaking: A single Firestorm achieves memory reads up to around 58GB/s, with memory writes coming in at 33-36GB/s. Most importantly, memory copies land in at 60 to 62GB/s depending if you’re using scalar or vector instructions. The fact that a single Firestorm core can almost saturate the memory controllers is astounding and something we’ve never seen in a design before.”
The memory bandwidth you get on the M1 is around what you would expect from a dual channel desktop with good RAM. So basically twice as fast as competing laptops.