How to fix Firefox Flash games lagging

Matthew Adams
by Matthew Adams
Windows & Software Expert
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  • Flash games are still popular today but users sometimes face game lags.
  • If you've ever wondered why are Flash games so laggy, the main cause is the browser.
  • For instance, at this moment, the best Flash games browser would be Opera.
  • Looking into the background tasks in your system should also fix game lagging. 
reduce Firefox flash game lag
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There are plenty of websites where you can still play Flash games in your browser. Such sites include games with high-paced gameplay that can be slowed down in Firefox and other browsers.

Lag is delayed server response times, and heavy lag can have a big impact on the game’s performance.

In order to have the best gaming experience on your browser, you need to take care of a few settings. Here we offer you some methods to do just that.

The steps written below are helpful if you encounter the following issues in any browser:

  • Flash games lag
  • Why are Flash games so laggy?
  • Flash player lag

How do I reduce the Firefox Flash game lags?

  1. Consider using another browser
  2. Disable Flash content rendering
  3. Reduce the Flash game graphical quality
  4. Configure the Hardware Acceleration setting
  5. Close running background software
  6. Close Firefox tabs and add-ons
  7. Clear the Flash game cache

1. Consider using another browser

Before following all of the troubleshooting steps listed below, you should first consider the possibility of replacing Firefox altogether.

Since playing flash games is what interests you most in this case, we recommend you try a web browser that advertises itself as the world’s first browser for gamers.

This browser is called Opera GX, and it is an ultra-lightweight browser created using the Chromium-engine. Everything about it screams that it is made for gamers, from the UI design to the integration of various gamer-oriented tools.

These include Twitch integration and a function called GX Control which features a RAM limiter, a bandwidth limiter, and more, all so that the browser can run i the background without affecting your gaming experience.

All things considered, if you want to play Flash games, why not do it in an environment that makes you feel like it is an AAA game instead?

You should also check out this guide on how to enable Flash-content in Opera.

Opera GX

Opera GX

Play flash games without any issues in the world's first web browser designed specifically for gamers.

2. Disable Flash content rendering

  • First, type about:config into Firefox’s address bar and press Enter .
flash game
  • Enter dom.ipc.plugins.asyncdrawing.enabled into the search bar at the top of the about:config page.
  • If dom.ipc.plugins.asyncdrawing.enabled is set to true, double-click it to switch it to false.
  • Now you’ve effectively switched off the Flash game rendering.

A previous Firefox 49.0.2 update increased lag in Flash games due to a new flag that enabled Flash game rendering in the browser.

This has slowed down games on gaming sites such as

3. Reduce the Flash game graphical quality

  • Open the Flash game Firefox.
  • Then you should right-click the Flash game to open its context menu and select Quality.
flash game2
  • That submenu includes three graphical settings. Select either the Medium or Low option to reduce the graphical quality of the game and lag.

4. Configure the Hardware Acceleration setting

  • First, you should right-click a Flash game window and select Settings.
  • Click the button at the bottom left corner of the window to open the Enable hardware acceleration option.
flash game3
  • If this option isn’t selected, click it to enable hardware acceleration.
    • Then your graphics card will display the Flash game.
  • If the Enable hardware acceleration option is already selected, you should still click its check box if games have lag.
    • This will remove any potential hardware compatibility issues with the Flash player, which can also reduce lag.

Flash games also include a hardware acceleration option. This can cause lag if selected or not, which might seem a little confusing.

Still facing game lag in Windows 10? Check out 6 free VPNs that will help to fix that.

5. Close running background software

flash game4
  • Click the Processes tab that displays both open applications and background processes.
  • Select third-party software background processes that might be hogging bandwidth, and then press the End task button to close them.

Background software can generate lag and slow down games. Firstly, all software hogs at least a little RAM and system resources, which generally slows down games.

Secondly, some programs will also hog bandwidth, which can generate lag for streaming media and Flash games. As such, you should have just the Firefox window open on your taskbar for the Flash games.

6. Close Firefox Tabs and Add-ons

Firefox tabs and add-ons also need some extra RAM. So close all the background page tabs open in the browser to ensure more RAM is available for the Flash games.

You should also switch add-ons off by selecting Open menu > Add-ons to open the tab directly below. Click Extensions and then press the Disable buttons beside the add-ons listed there.

flash game5

7. Clear the Flash game cache

  • Open the Flash game that lags in Firefox.
  • Next, you should right-click the Flash game and select Global Settings from the context menu.
flash game6
  • Select the Advanced tab.
flash game7
  • Press the Delete All button and then click Delete Data to clear the Flash cache.
  • Then close the game website and Flash Player Settings Manager window.
  • Open the game website in Firefox again and reload the Flash game.

So that’s how you can reduce Flash game lag in Firefox and other browsers. Now the games will run quicker and more smoothly than before.e

Editor's Note: This article was originally published in November 2016 and was revamped and updated in January 2021 for freshness, accuracy, and comprehensiveness.