Earlier quoted context omitted.
> 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…
The overall bandwidth isn't affected much by the distance alone. Latency, yes, in the sense that the signal literally has to travel further, but that difference is miniscule (like 1/10th of a nanosecond) compared to overall DDR access latencies. 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…
I wonder about the practicalities of going to SRAM for main memory. I doubt silicon real estate would be the limiting factor (1T1C to 6T, isn't it?) and Apple charges a king's ransom for RAM anyway. Power might be a problem though. Does anyone have figures for SRAM power consumption on modern processes?