[aseipp]

You can only meaningfully determine that if you assume the die is more-or-less the same between the two versions. It is not; the M3 Pro has many changes, the perf/efficiency core ratio is different, they have different amounts of per-core cache, max clock rate, etc. That gets bigger as you move away from the CPU cores (e.g. the GPU is a big architecture change.)

For example, the M3 Pro has 6+6 P/E cores, versus the M2 Pro's 8+4. That is a big change that impacts performance, but can only be truly measured "globally" on a specific workload. The M3 Pro does do better for many workloads despite that. Maybe we could assume the improvement in transistor density gave them enough performance uplift, they were able to get rid of 2 P cores and still come out ahead. Does that mean that 3nm is "bad"? No, it meant it was good enough that it allowed them to make a different tradeoff.

"How much uplift comes from this one exact thing" is not really a super simple question to answer in this case, unfortunately, and there are many factors to control for.

[topper-123]

All true, but the same apples to the M1 to M3 comparison, and the architectural differences are likely even greater than between the M2 and M3.

[aseipp]

Yes, that's my point. The M1 Pro is also 5nm, would you say that the M1 losing badly to the M3 means 3nm is way better than 5nm? No, the architectural differences mean that trying to derive or compare performance characteristics of the underlying lithographic process is mostly difficult or totally pointless. It doesn't matter whether you use the M1 or the M2 as the baseline. You need to use the same design to understand the lithographic differences, and these aren't the same designs. It's only one small part of the equation.

So going back to your original question, I think the reason people compare the M1 vs the M3, and not M2 vs M3, has nothing to do with making 3nm "look good" or whatever. The reason is more mundane: it's because that's what people would probably upgrade from. Because of all the differences, the only way to know whether an upgrade is worth it is to do workload comparisons, not one-to-one architectural/litho comparisons.