Summary:
Many games see noticeable improvements, but how much of an improvement will vary. Games that are bottlenecked by GPU or memory bandwidth benefit significantly, whereas CPU-bound titles only see small improvements.
Arkham Knight, famously one of the Switch’s worst ports, is now a playable 30fps. Dragon Quest Builders 2 is… playable but still not great, building as much as possible to stress test the hardware can drop to single digit framerates on Switch 1, that’s now around ~20-22fps here. These are the two most demanding titles tested, which means that most everything else came out pretty good.
The obvious caveat here is that games cannot exceed hardcoded targets. Games with uncapped framerates and dynamic resolution will be able to take advantage, but capped framerates and fixed resolutions must remain so.
That’s objectively incorrect though. It’s an entirely new chip based on a different architecture. Switch 1 games are actually run through a translation layer, which is why a small number of them still don’t work on Switch 2 currently.