So if I understand correctly the new format has performance benefits, partly due to shorter traces and a better connection to the motherboard. So would this format eventually come to desktop too?
From my limited understanding, the specific performance benefits in the article come from it being DDR5X memory. LP (Low Power) DDR needs to be very close to the CPU (short traces) because of how much less power it consumes. DDR5x should have the same bandwidth as LPDDR5x, it would just consume more power. Up until now, there wasn't a way to have "socketed" LPDDR, so it was soldered to the motherboard or even placed in the same package as the CPU (Apple M-series CPUs have the RAM in the same package as the CPU). Now they have a standard way to basically strap down a BGA chip that will live right next to the CPU.
DDR5x isn't a thing. LPDDR memories and DDR memories have a significant differences in how the interface works; LPDDR isn't just a low-voltage version of DDR, and it's mostly coincidental that the generation numbering lines up (as opposed to DDR vs GDDR generation numbering).
Ah, I didn't know LPDDR and DDR were fully different things! I always assumed since their generation numbers lined up they were based on each other.
I think this is performance relative to SO-DIMMs, not relative to desktop/server DIMMs.
Performance benefits versus other replaceable RAM. It's still a small (on the order of 10%) regression from the on-die RAM that Apple has been popularising
in-package ram is certainly not an apple thing. if anything, it's a phone thing.
Indeed, but I don't know of any other PC manufacturers who were widely using it before Apple went down the soldered-RAM path?