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Speed up Firefox

I’ve seen a lot of gimmicky hacks to speed up Firefox, and you probably have too. But chances are Firefox ran just fine when you started, then it slowed down over time. Here’s my collection of tips to restore Firefox’s performance if Firefox is slow.

I’ve been using Firefox since 2002, when it was called Phoenix. I’m also a longtime performance enthusiast. And I wrote one of the very first books about improving computer performance. Naturally, I collected a lot of speed tips along the way. These days I use Chrome a lot too, but Firefox and I are old friends.

If Firefox started out fast but became unbearably slow, whether it was gradual or sudden, try these first three things first. There’s no about:config hack that will speed up Firefox when the problem is an add-on or your user profile.

After you do two or three of these first three things, then dig into about:config to get some additional speed.

Move your user profile to a ramdisk

Most computers have plenty of RAM to spare these days. You can put it to good use by making a dedicated disk drive for Firefox out of it. This is a modern application of an idea that goes back to the 1980s. If you have more than 8 GB of RAM, it’s very worthwhile and makes Firefox blazing fast, because memory is an order of magnitude faster than even the fastest SSD, let alone a hard disk. So if you’re running Windows, check out my guide to Firefox and ramdisks.

If you run an operating system other than Windows, you can probably adapt my ramdisk trick to that. I don’t know anything about ramdisks on Macintoshes. But I’ll try to write up something about Linux in the near future.

Clean up your Firefox database

Firefox keeps most of your user data in a database, and over time, that database gets bloated and slows things down. Cleaning up that database will, more often than not, restore performance to what it used to be. I have two guides for that, a manual way and an automatic way. This is by far the second best thing you can do to make Firefox fast.

Find slow add-ons

Sometimes it’s not Firefox that’s slow, but one of your add-ons. Here’s how to find which add-ons are slowing you down. If you don’t really need that functionality, consider disabling that add-on. Or look for an alternative that provides similar functionality but isn’t as hard on your system.

About:config hacks

These final tricks require you to type about:config in your address bar. Firefox will give you a scary warning to click through. If you’re comfortable doing Windows registry hacks, these tricks are old hat. If you aren’t, consider using an add-on like Fasterfox.

Once you have the about:config screen pulled up, click in the search box and search for the following parameters, in order, and set them to the values I indicate. Usually you only have to type the first few characters of each parameter for it to show up.

You can usually tell what these items do. Disabling animation makes the user interface snappier. The items that have to do with networking adjust Firefox to take better advantage of fast Internet connections.

  • browser.cache.use_new_backend – set to 1
  • – set to False
  • browser.fullscreen.animate – set to 0
  • browser.preferences.animateFadeIn – set to False
  • browser.tabs.animate – set to False
  • config.trim_on_maximize – set to True
  • network.http.pipelining – set to True
  • network.http.pipelining.maxrequests – set to 10-15 as long as you have lots of memory. Don’t set it too high as this can harm performance.
  • network.http.proxy.pipelining – set to True
  • network.prefetch-next – set to False but only if you have a slow Internet connection
  • security.dialog_enable_delay – set to 0

Is it your Internet connection?

The other thing to check is whether it’s Firefox that’s slow, or your Internet connection. If another browser is also slow, it’s more likely your problem is elsewhere. I have some tips for sizing an Internet connection, and believe it or not, replacing your router can make a tremendous difference.

Speed up your OS

If you’ve recently upgraded to Windows 10 and your system seems more sluggish than it used to be, it may not be your imagination. Here’s my guide to optimizing Windows 10.

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