Earlier quoted context omitted.
The M1 still uses DDR memory at the end of the day, it's just physically closer to the core. This is in contrast to L3 which is actual SRAM on the core. The DDR being closer to the core may or may not allow the memory to run at higher speeds due to better signal integrity, but you can purchase DDR4-5333 today whereas the M1 uses 4266. The real advantage is the M1 Max uses 8 channels, which is impressive considering t…
> The DDR being closer to the core may or may not allow the memory to run at higher speeds due to better signal integrity, but you can purchase DDR4-5333 today whereas the M1 uses 4266. My understanding is that bringing the RAM closer increases the bandwidth (better latency and larger buses), not necessarily the speed of the RAM dies. Also, if I am not mistaken, the RAM in the new M1s is LP-DDR5 (I read that, but it…
Better signal integrity could allow for larger busses, but I don't think this is actually a single 512 bit bus. I think it's multiple channels of smaller busses (32 or 64 bit). There's a big difference from an electrical design perspective (byte lane skew requirements are harder to meet when you have 64 of them). That said, I think multiple channels is better anyway.
The original M1 used LPDDR4 but I think the new ones use some form of DDR5.