How to reduce Firefox flash game lag

Matthew Adams
by Matthew Adams
Windows & Software Expert
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  • Mozilla Firefox is one of the most popular web browsers out there as of now.
  • The guide below will teach you how to stop flash games from lagging in Firefox.
  • To read more about this amazing tool, head over to our dedicated Firefox Hub.
  • If you're into Flash games, check out our dedicated Gaming section as well.
reduce Firefox flash game lag

There are plenty of websites where you can play Flash games in your browser. These sites include games with high pace gameplay that lag can slow down in Firefox and other browsers.

Lag is delayed server response times, and heavy lag can have a big impact on the game’s gameplay. Here are a few ways that you can reduce Flash game lag in Firefox.

In order to have the best gaming experience on your Firefox 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 also helpful if you encounter the following issues:

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

How do I reduce Firefox flash game lag?

  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?

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 to open the page in the shot below.

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 as below.

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 in the snapshot below.

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.

5. Close running background software

  • Right-click the Windows taskbar and select Task Manager to open the window below.

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 a 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 to open the window directly below.

flash game6

  • Select the Advanced tab in the shot below.

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.

Editor’s Note: This post was originally published in May 2019 and has been since revamped and updated in August 2020 for freshness, accuracy, and comprehensiveness.