Remember the era of PC games that would run at double speed if you unlocked their draconian fps limits? It's rare for PC games these days not to support dynamic framerates, but it's more common on consoles like the Nintendo Switch, where developers know exactly how much (or how little) processing power they have to work with. The Legend of Zelda: Tears of the Kingdom is designed with a 30 fps cap, and mods have already been able to remove that cap and trick the game into running at 60 fps… if your PC can handle it. But given Tears of the Kingdom's early state of emulation, not even a mighty gaming rig can keep Tears of the Kingdom running at 60 fps all the time.
And when the framerate drops, get ready for slow motion.
Why does this happen in emulation, when most games can handle a drop in framerate without also slowing down the game's internal clock?
"Typically PC games are not bound to the rendering speed, but instead the game logic runs at the same speed, no matter what fps you reach," explains veteran emulation programmer Robert Peip, who's currently developing a Nintendo 64 core for the MiSTer project. Peip says that you can see this kind of slowdown in modern games in extreme cases—if you drop below 5 fps, for example, the game logic probably can't function normally—but they can typically tolerate a fair amount of fluctuation.
"In emulation there is sometimes a hard fps limit, eg, in Breath of the Wild the game logic for physics was bound to 30 fps max. That's why mods for 60 fps are needed. When you apply a 60 fps mod and cannot reach it, the game will not update the game logic often enough and the game slows down. This was even more present in older 2D titles that ran at fixed fps all the time."
Slowdown isn't the only problem with modding Tears of the Kingdom to 60 fps—the pre-rendered cutscenes run at double speed, since, again, the game was programmed to expect to run at a specific speed.
At the pace emulator developers are currently moving, a much more consistent 60 fps may be viable in the coming months through optimization. But the more timely solution is a mod for the game that allows it to run with a dynamic framerate, meaning the game logic will still behave consistently at 60 fps or, say, 37 fps.
Early Friday, a Reddit poster published a "beta" dynamic FPS mod for Tears of the Kingdom, claiming it works alongside the existing 60 fps mod to smooth out performance when the framerate drops. It's still a work-in-progress, with some notable issues, including some animations like fire still playing at incorrect speeds, and cutscenes still running in double time. It also doesn't solve an odd side effect of the 60 fps patch, which causes the screen to go black while swapping weapons.
Mods like these for emulated games are typically memory patches, tweaking certain values in memory to temporarily alter how it functions. It's a lighter-touch form of modding than actually changing a game's files, since all you have to do is drop a small text file into a mod folder that the emulator will read when you load up the game. But making a memory patch requires figuring out how a game functions, which typically requires some study and a good bit of trial and error.
So how did the mods above arrive so quickly after Tears of the Kingdom's release? Well… they didn't.
Several of these patches arrived before Tears of the Kingdom was even out, giving them an uncomfortably blatant link to piracy. The redditor behind the dynamic fps mod has been posting hacks on the r/NewYuzuPiracy subreddit since Tears of the Kingdom leaked, and the 60 fps mod was also posted well before the official release. That makes me want to steer clear of both, even if the mod in question is really just a tiny text file with a dozen lines of code.
That connection to piracy won't stop many users from downloading them, and now that the game is out in the wild it's easy to overlook, or not even realize, who created the mods and how they did so. But it's a bad look for the emulation scene in general—and for players who dutifully dump their own copies of Tears of the Kingdom to play via emulation, it's unfortunate the current mods weren't created the same way, playing by the rules.
Now that Tears of the Kingdom is out, there are dedicated modders who are now on the case. They've previously come up with ultrawide aspect ratio hacks, disabled dynamic resolution, and unlocked framerates in other Switch games, as listed on the Yuzu emulator's site here. It should just be a matter of time until they nail down a mod that enables a dynamic framerate without the black screen issue that affects the current 60 fps mod. Until then, I'll be sticking to the native, unmodified 30 fps, which is already looking very promising at up to 4K.