“ M1 unifies its high‑bandwidth, low‑latency memory into a single pool within a custom package. As a result, all of the technologies in the SoC can access the same data without copying it between multiple pools of memory . This dramatically improves performance and power efficiency.”
“Apple is using high-bandwidth memory here. The memory is closer to the CPU (and other components), and it’s just faster to access than it would be to access a traditional RAM chip connected to a motherboard via a socket interface.”
“… because all the aspects of the processor can access all of the system memory, there’s no performance hit when the graphics cores need to access something that was previously being accessed by a processor core. On other systems, the data has to be copied from one portion of memory to another—but on the M1, it’s just instantly accessible.”