How to Stop Minecraft From Eating Your CPU While Alt-Tabbed

When you tab out of Minecraft to check a wiki or answer a message, the game keeps rendering frames you can't even see. Dynamic FPS fixes this by detecting when the window loses focus and throttling the game down. Here's how to make sure it's actually doing that.

Confirm the mod is reacting to focus loss

1. Launch your world and open the Dynamic FPS config screen (usually through Mod Menu or the mod's own config key).

2. Find the section dealing with the unfocused state. This is the state the game enters when another window sits on top of it but Minecraft is still visible behind it.

3. Make sure the frame rate for this state is set low but not zero — a low value keeps the game responsive when you click back in, while still freeing up your CPU.

4. Also check the invisible state, which triggers when the window is fully covered or minimized. This is the one you can safely push to the most aggressive setting, since nothing is being drawn on screen anyway.

5. Apply the changes, then alt-tab away and watch your system monitor. You should see Minecraft's CPU usage drop sharply within a second or two.

Why this matters

Rendering even a static menu costs GPU and CPU time. By letting Dynamic FPS idle the game when you're not looking at it, you free resources for whatever you tabbed over to do — a browser, a video call, or another game. If you run a server on the same machine, this headroom matters even more.