[Windows] app frame rate unstable since Flutter 3.35.0

Steps to reproduce

Run a simple Windows Flutter app on 3.35.0.
Observe FPS without doing anything.
Do some input (drag mouse) and notice FPS briefly goes up.

Expected results

App should run stable at the monitor refresh rate.

Actual results

My monitor refresh rate is 165Hz, but the app usually runs only 60–70 FPS.

When I interact with the app (like mouse dragging), the FPS jumps up to full refresh rate.

Because of this, animations feel not smooth. Before interaction, they are slower, after interaction they suddenly jump, it looks visually laggy. I am making a game with animations, so this problem is very noticeable for me。

Code sample

import 'package:flame/game.dart';
import 'package:flutter/material.dart';
import 'package:flame/components.dart';

// Example using flame engine -> flame: ^1.30.1
void main() {
  WidgetsFlutterBinding.ensureInitialized();
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(body: GameWidget(game: MyGame())),
    );
  }
}

class MyGame extends FlameGame {
  late MyRectangle _rectangle;
  late FpsTextComponent _fps;

  MyGame({super.camera});

  @override
  Future<void> onLoad() async {
    super.onLoad();
    await _addComponents();
  }

  @override
  void onGameResize(Vector2 size) {
    super.onGameResize(size);
    if (isMounted) {
      _rectangle.position = size / 2;
      _fps.position = size / 2;
    }
  }

  Future<void> _addComponents() async {
    _rectangle = MyRectangle(position: size / 2, size: Vector2(size.x / 2, 10));
    add(_rectangle);

    _fps = FpsTextComponent(position: size / 2, anchor: Anchor.center);
    add(_fps);
  }
}

class MyRectangle extends RectangleComponent {
  final double rotationSpeed;

  MyRectangle({
    super.position,
    required super.size,
    Anchor? anchor,
    this.rotationSpeed = 60.0,
  }) : super(anchor: anchor ?? Anchor.center);

  @override
  void update(double dt) {
    super.update(dt);
    angle += rotationSpeed * dt;
  }
}

Screenshots or Video

Video demonstration

Note: The videos are a side-by-side comparison of two Windows apps. The left side uses Flutter 3.35.0, and the right side uses Flutter 3.32.0.(The FPS difference may not be very obvious in the video because the recording frame rate is low. However, the FPS counter is visible in the video, and you can also run the code yourself to see the problem.)

flutter_frame_rate_issue_20250909.mp4

Logs

[Paste your logs here]

Flutter Doctor output

Doctor output

[√] Flutter (Channel stable, 3.35.3, on Microsoft Windows [版本 10.0.26100.4946], locale zh-CN) [293ms]
    • Flutter version 3.35.3 on channel stable at C:\Users\74218\fvm\versions\stable
    • Upstream repository https://github.com/flutter/flutter.git
    • Framework revision a402d9a437 (6 days ago), 2025-09-03 14:54:31 -0700
    • Engine revision ddf47dd3ff
    • Dart version 3.9.2
    • DevTools version 2.48.0
    • Pub download mirror https://pub.flutter-io.cn
    • Flutter download mirror https://storage.flutter-io.cn
    • Feature flags: enable-web, enable-linux-desktop, enable-macos-desktop, enable-windows-desktop, enable-android, enable-ios, cli-animations, 
      enable-lldb-debugging

[√] Windows Version (11 专业版 64-bit, 24H2, 2009) [2.3s]

[√] Android toolchain - develop for Android devices (Android SDK version 35.0.0) [4.8s]
    • Android SDK at D:\software\Android\Sdk
    • Emulator version 34.2.16.0 (build_id 12038310) (CL:N/A)
    • Platform android-36, build-tools 35.0.0
    • ANDROID_HOME = D:\software\Android\Sdk
    • Java binary at: C:\Program Files\Java\jdk-19\bin\java
      This JDK is specified in your Flutter configuration.
      To change the current JDK, run: `flutter config --jdk-dir="path/to/jdk"`.
    • Java version Java(TM) SE Runtime Environment (build 19.0.2+7-44)
    • All Android licenses accepted.

[√] Chrome - develop for the web [77ms]
    • Chrome at C:\Program Files\Google\Chrome\Application\chrome.exe

[√] Visual Studio - develop Windows apps (Visual Studio Community 2022 17.10.1) [75ms]
    • Visual Studio at D:\software\vs2022
    • Visual Studio Community 2022 version 17.10.34928.147
    • Windows 10 SDK version 10.0.22621.0

[√] Android Studio (version 2022.1) [10ms]
    • Android Studio at C:\Program Files\Android\Android Studio
    • Flutter plugin can be installed from:
       https://plugins.jetbrains.com/plugin/9212-flutter
    • Dart plugin can be installed from:
       https://plugins.jetbrains.com/plugin/6351-dart
    • Java version OpenJDK Runtime Environment (build 11.0.15+0-b2043.56-9505619)

[√] VS Code (version 1.103.2) [8ms]
    • VS Code at C:\Users\74218\AppData\Local\Programs\Microsoft VS Code
    • Flutter extension version 3.118.0

[√] Connected device (3 available) [223ms]
    • Windows (desktop) • windows • windows-x64    • Microsoft Windows [版本 10.0.26100.4946]
    • Chrome (web)      • chrome  • web-javascript • Google Chrome 140.0.7339.80
    • Edge (web)        • edge    • web-javascript • Microsoft Edge 139.0.3405.125

[!] Network resources [361ms]
    X A cryptographic error occurred while checking "https://github.com/": Connection terminated during handshake
      You may be experiencing a man-in-the-middle attack, your network may be compromised, or you may have malware installed on your computer.   

! Doctor found issues in 1 category.

@JankLai

@JankLai We verified on Windows 11 without monitor as we don't have high refresh rate external monitor and below is comparison between 3.32 and 3.35+:

fps3.32.mp4

fps3.35.mp4

If you see, there isn't any difference between the frame rates. Since you are using external monitor I presume, the high refresh rate of it could be causing the reported behavior. The FPS in our case was limited to ~60. Can you check without external monitor to see if you still see reported behavior ?

@darshankawar

@darshankawar Hi, thank you for checking this issue.

I saw you tested on a 60Hz device. But my problem is happening on a high refresh rate monitor (165Hz).

I think the problem is about how the app works on high refresh rate monitors. A solution can't be just using a 60Hz monitor, because many users have 144Hz or 165Hz monitors. (My personal guess is maybe the new Flutter version is now limiting the default FPS to around 60 on Windows to save power, and it only unlocks the full refresh rate when it detects user interaction.)

My goal is to ensure the app performs consistently and smoothly on all modern displays, including those with high refresh rates. Could you please check this issue again, thinking about the FPS going up and down on a high refresh rate monitor? Thank you.

@JankLai

Thanks for the update @JankLai. Please check this issue which has same discussion about refresh rate on windows as well, to see if it helps further in your case or not.

@darshankawar

@darshankawar Thank you for providing the link. I have checked it. But my app was working fine on Flutter 3.32.0. The frame rate issue started after I updated to version 3.35.0.

This means it could be a new bug in the new version. I hope this information is helpful for you to find the issue.

Thanks for the update. Keeping the issue open for team's tracking as we are unable to verify / replicate due to lack of high refresh external monitor.

@JankLai

I think this might be caused by SetTimer resolution which is rather coarse for compatibility reasons.

@JankLai, does the problem persist when you call timeBeginPeriod(1) at the beginning on your application?

https://learn.microsoft.com/en-us/windows/win32/api/timeapi/nf-timeapi-timebeginperiod

I might be that timeBeginPeriod will not directly affect WM_TIMER resolution, in which case we'll need to use different mechanism to wake up the loop.

@knopp

@knopp Hi, I just tested with timeBeginPeriod(1) (added in main.cpp before running the app), but unfortunately the issue still persists.

Yeah, I just tested it too, it unfortunately doesn't affect WM_TIMER granularity. We're going to need a bigger hammer than that.

fix: flutter/flutter/issues/175135

解决 flutter/flutter/issues/175135

[win32] Runloop should use high resolution timer and avoid deadlock (#…

[win32] Runloop should use high resolution timer and avoid deadlock (f…

This thread has been automatically locked since there has not been any recent activity after it was closed. If you are still experiencing a similar issue, please open a new bug, including the output of flutter doctor -v and a minimal reproduction of the issue.

[win32] Runloop should use high resolution timer and avoid deadlock (f…

[win32] Runloop should use high resolution timer and avoid deadlock (…

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[Windows] app frame rate unstable since Flutter 3.35.0 #175135

Steps to reproduce

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Actual results

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Screenshots or Video

Logs

Flutter Doctor output

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[Windows] app frame rate unstable since Flutter 3.35.0 #175135

Description

Steps to reproduce

Expected results

Actual results

Code sample

Screenshots or Video

Logs

Flutter Doctor output

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darshankawar commented on Sep 10, 2025

JankLai commented on Sep 10, 2025

darshankawar commented on Sep 11, 2025

JankLai commented on Sep 11, 2025

darshankawar commented on Sep 11, 2025

7 remaining items

knopp commented on Sep 24, 2025

knopp commented on Sep 24, 2025

JankLai commented on Sep 24, 2025

knopp commented on Sep 25, 2025

github-actions commented on Oct 16, 2025

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