Nintendo's open-world masterpiece, The Legend of Zelda: Breath of the Wild, is one of the rare open-world games that launched and didn't have a ton of problems. What few problems it did have, Nintendo issued a patch to fix them.
In the patch notes for update 1.1.1, they keep it brief but mention that adjustments were made to make the gameplay experience more enjoyable for end users. Some Wii U owners noticed that there were fewer frame-drops in some areas, where-as Nintendo Switch owners most certainly saw some big improvements during combat and exploration in Breath of the Wild, where the game no longer loses as many frames during Link's adventures.
The FPS gains aren't huge. The game was already targeting 30fps at a fixed rate, and Nintendo's patch mostly attempts to get the game to run at the designated cap in as many areas as possible.
Well before the game's release -- back during the promotional marketing campaign when Nintendo was showing off the Switch to journalists -- Digital Foundry managed to get in a video about the frame-rate performance of Breath of the Wild and they discovered some odd inconsistencies. Not all of the frame-drops in the game, on the Switch version, were related to hardware performance drains. For instance, in one case they were just running through a field and the frame-rates took a massive dive, where-as in the exact same area on the Wii U version there were no drops.
Digital Foundry speculated that it was some sort of misconfiguration on the software side of utilizing the Switch's GPU or memory management. A lot of other users and reviewers also noted that the game also suffered from some frame-drops during some key moments of gameplay. Most people noted that combat with the goblins resulted in the frames dropping rather significantly.
The combat with the goblins makes sense because the game is attempting to process a lot of different potential AI routines, as well as take into account some of the physics-based combat mechanics and features, and other sub-routines that may also affect the combat, such as weather, or nearby animals, or the weapons that Link is using.
The Legend of Zelda: Breath of the Wild is a very taxing game, and a lot of people were just amazed that Nintendo managed to squeeze the game onto the Wii U in the way that they did, and manage to keep the frames consistent at 30fps for the most part.
The Nintendo Switch version of the game was a little bit more of a mystery as to why the frames would drop, but given that the Switch version is actually a port from the Wii U version, it's not surprising that it had some minor hiccups in the performance area.
The patch addresses the game in the docked form when running at 900p, which is where most of the frame-rate issues took place. So performance should still be a-okay when playing The Legend of Zelda: Breath of the Wild undocked at 720p.