[candeira]

I could be wrong about this but, if I had a guess, I'd say the 24GB M5 chips/systems exist due to binning.

Apple is designing and manufacturing a chip/chipset/system with 32GB with integrated memory. During QA, parts that have one non-conformant 8GB internal module out of the four are reused in a cheaper (but still functional) 24GB product line rather than thrown away.

Market segmentation also has its hand in how the final products are priced and sold, but my strong guess is that, if Apple could produce 32GB systems with perfect yield, they would, and the 24GB system would not exist.

[angoragoats]

The memory is not on-die, it’s separate (completely standard) memory chips, either DDR4 or DDR5 depending on which M-series CPU you’re looking at. So binning doesn’t really apply.

[candeira]

Seems like there's a misunderstanding on my part here. <reads more>

Ah, the memory is integrated in the same package (the "chip" that gets soldered onto the motherboard) as the integrated CPU/GPU, and I had understood that correctly. However, I had incorrectly surmised that it was built into the same silicon die.

Thanks for the correction!

Lesson: TIL about the difference between System-In-a-Package (SIP) and System-On-a-Chip, and how I had misunderstood the Apple Silicon M series processors to be SoCs when they're SiPs.

[angoragoats]

No worries! It’s made more difficult to understand by 1) Apple’s marketing, which does a great job of tricking people into thinking that the memory is actually integrated into the die without actually saying so, and 2) the fast-and-loose use of the SoC and SiP terms, which are often used interchangeably, including by Apple in official marketing materials [1].

[1] https://www.apple.com/newsroom/2023/06/apple-introduces-m2-u...