Wednesday, January 17, 2024

Game Mode in Sonoma

Andrew Cunningham:

Sonoma brings two more features that point to Apple’s newfound seriousness about gaming on the Mac. The first is Game Mode. It’s analogous to a Windows 11 feature of the exact same name, and they’re functionally similar in that they both promise to deprioritize background tasks to keep games running smoothly.

Apple’s version of Game Mode also promises to lower Bluetooth latency for connected input devices and wireless headphones.

I tested with a pair of non-AirPod Bluetooth earbuds and a DualShock 4 controller connected to an M2 MacBook Air, mostly playing games downloaded from Steam. Game Mode started reliably when games began and disappeared when they were closed.

I can’t say I noticed a difference in input latency, even in twitchier 2D games where I’m more sensitive to that kind of thing. But I definitely noticed an improvement in audio latency, where normally I’d need to switch to my earbuds’ low-latency Game Mode to get lag-free audio.

John Vorhees:

In typical Apple fashion, Game Mode isn’t something you turn on. It’s enabled as soon as you start a game.

Tim Hardwick:

When you enter full screen in this way, a Game mode menu appears in the menu bar. You can use this menu to confirm that Game mode is turned on for your game.

Howard Oakley:

Apple explains that this “optimizes your gaming experience by giving your game the highest priority access to your CPU and GPU, lowering usage for background tasks. And it doubles the Bluetooth sampling rate, which reduces input latency and audio latency for wireless accessories like game controllers and AirPods.”


gamepolicyd works with RunningBoard to designate gameconsole and some other services as “Game Mode Critical Services”.

Howard Oakley:

Perhaps the best overview of the effects of Game Mode on the CPU and GPU is this chart showing power consumption for the whole CPU and GPU during a run in Game Mode.


Assembling these, it’s apparent that during Game Mode, the game was given exclusive use of the two E cores, and threads from other processes fixed at low QoS, which would require them to be run on the E cores, were kept waiting. The game’s threads were run on a combination of E and P cores, with much of their load being concentrated on the E cores. This appears to be energy-efficient, and ideal for use on notebooks running on battery power.

Howard Oakley:

This article looks at another atypical situation, when running a macOS virtual machine (VM) assigned a set number of virtual cores. How does macOS Sonoma handle that?


2 Comments RSS · Twitter · Mastodon

I wonder if Game Mode does the other thing games always used to do on the Mac - drop the screen resolution to 25-50% of that used for the same game in Windows. Really easy to hide that if you force games to run full-screen.

Reminds me of when I wrote boot disks for my dad's PC in the late nineties.

Leave a Comment