macOS Monterey was announced during this week's WWDC keynote, and in a subsequent session, the company revealed that the upcoming update will include support for variable refresh rates.

This is because Monterey will allow all M1-based Macs (and many recent Intel-based models) to dynamically adjust the refresh rate of the display and synchronize it with the frame rate of games. Of course, the display must also support Adaptive-Sync, a feature of the VESA DisplayPort 1.2a standard.

In short, this new feature comes with an important caveat. While all M1-based Macs and many recent Intel-based Macs now support variable refresh rates in macOS Monterey, you still need to connect your machine to a compatible monitor to realize its benefits.

Since iMac and MacBook screens are fixed-rate displays, neither supports this feature. To see this feature in action, a Mac with Monterey must be connected to an external display that supports Adaptive-Sync. [Adaptive-Sync mode tells the Mac to dynamically adjust the display's refresh rate and only refresh when it is ready to display a new frame.

To enable Adaptive-Sync on macOS Monterey, you must first make sure you have a compatible Mac: Apple representatives have confirmed that so far only Apple Silicon Macs and "recent Intel-based Macs" are Adaptive-Sync is supported.

If you have a compatible machine, you will see a new variable refresh rate option in the Display section of the System Preferences menu. Simply turning this on should immediately improve game performance. Note, however, that for variable refresh rate to work, the game must be run in full-screen mode.

The full release of macOS Monterey is scheduled for the fall, but a developer beta is currently available, and a public beta will be released in July to give users an early taste of this feature.