The latest patch for Ratchet and Clank: Rift Apart has given the game a small but significant performance boost when playing using its fidelity mode on 120Hz displays. According to the patch notes for version 1.002 of the game, fidelity mode now runs at 40 frames per second when used with 120Hz displays, up from the 30 frames per second previously. That’s over a 30 percent improvement, which should make the game look a lot smoother and feel a lot more responsive to play in this mode.

It’s a change that mainly affects just one of the three display modes the PS5 game shipped with, but it’s a fascinating example of the kinds of things that will become possible as 120Hz TVs become the norm. It’s also an interesting workaround for Sony’s current lack of support for variable refresh rates (VRR) on its console, a feature which the company has said it plans to add in a future software update.

For the uninitiated, Rift Apart originally shipped with three display modes: Fidelity, Performance, and Performance RT. Performance runs the game without ray tracing at 60 frames per second, at a resolution of between 1620p and 1800p, according to Digital Foundry. Performance RT adds ray tracing support and still runs at 60fps, but resolution is lower at between 1080p and 1440p. Finally, there’s fidelity mode, where you get ray tracing and the highest resolutions of between 1800p and 2160p (full 4K), but at the cost of frame rate, which was previously limited to 30fps.

But now, if you’ve got a compatible 120Hz TV, that frame rate sits at 40fps rather than 30. You might be confused about why this requires a 120Hz TV in the first place, and why it won’t work on regular 60Hz TVs. After all, 60 is more than 40, which suggests that it should be possible.

The reason is that in order for motion to display smoothly, a game’s frames should ideally divide equally across a display’s refresh rate. It’s easy for a 60Hz display to display a 30fps game, for example, because it will show a new frame once every couple of refreshes. But other frame rates that don’t equally divide into 60 are more complicated. It’s why TV manufacturers have to put in a lot of effort to make sure that movies (which are typically shown at 24 frames per second) can play smoothly and without judder on otherwise 60Hz displays.

That’s why a 120Hz TV makes smooth 40fps content possible, because each frame can be divided across three refreshes. And users on ResetEra report that playing the game in this mode feels a lot smoother than the previous 30fps mode.

It’s worth noting that Rift Apart did originally ship with 120Hz support. But this didn’t affect the game’s frame rate, and instead was designed to reduce input latency. The mode was later removed over the compatibility issues it caused. With its return, however, input latency should also see improvements.

Of course, the ideal future is for everything to support variable refresh rates, which allow screens to dynamically scale to whatever frame rate a game is able to produce, rather than being limited to arbitrary frame rate caps. The feature is already supported on Microsoft’s Xbox Series X and S consoles, most modern PC graphics cards, and a growing number of HDMI 2.1-equipped TVs. But there’s still no sign of the update for PS5 consoles.

https://www.theverge.com/2021/7/1/22558816/ratchet-and-clank-rift-apart-fidelity-mode-40fps-120hz-30fps-refresh-rate