The M2 Max manufactured on the N5P while the Snapdragon X Elite is on the N4. The N4 node is an enhanced 5 NM node so there isn't much difference there.
TSMC N4 is supposed to have 6% higher density and approximately 4% better performance (at the same power), than N5.
There's also N4P, which ups the performance advantage to 11%.
I'm not surprised the numbers basically line up with an M2 Max (I guess I am a little because I don't believe the Snapdragon X Elite has the memory on package, but it does have 2 extra cores) .
I'm not sure if they've said how it's connected, but they
did say they're using LPDDR5X-8533, which I'm not sure you can do off-package. That's certainly faster than the LPDDR5-6400 the M2 uses. That's enough to net them 136 GB/s of bandwidth, at only 128-bit. It seems the main benefit of putting it on-package is really power savings, which you can turn around and spend on frequency, if you want the additional performance.
Unlike desktop PCs, phones have long been able to adjust their memory frequency on-demand. I'm sure their new laptop SoC is doing this with memory, as well. So, even though it might burn a lot of power at 8533 MT/s, it's only running that fast when under heavy load. The rest of the time, they can scale back and enjoy some power savings.
Remember Apple has exclusivity rights to the TSMC's 3NM node until the end of the year ish (don't remember the exact date 3NM opens for other customers).
That's irrelevant
now, because Qualcomm said devices wouldn't be shipping until mid 2024. However, it probably factored into their decision to use N4, since I'm sure they expected to have it in shipping devices
this year.