Google Chrome led the way, then Internet Explorer 9 and Firefox 4 followed—modern browsers are becoming less cluttered, render websites faster, launch even quicker, and still add tons of new features with every new release. However, there’s still one thing that has a negative effect on all these fantastic improvements and that’s poorly written, low-performance add-ons.
In this blog post, I’ll show you how to spot resource hogs in Firefox 4 and disable them safely.
Why is Firefox 4 so slow?
In a perfect world, Firefox 4 would take just a few seconds or even faster to start up (if you have an SSD drive and a fast processor). However, many users install add-ons to get more out of their browser—language translators, website comparison tools, streaming video grabbers and other plug-ins. While this makes Firefox a handier application, you need to be careful because many add-ons slow things down quite a bit. In fact, the more versatile and functional the add-on, the more drastic the performance drop:
- Browsing: Downloads and opening websites take longer
- Tabs: Longer delays when opening up a new tab or switching between tabs
- Startup: Launching the browser takes more time than usual.
So how does this happen? Add-ons load all of their features into memory at once—even if a user just needs one specific function of the add-on. Also, some add-ons are just poorly written and generate heavy file I/O. There are frequently components in these add-ons that are so highly compressed that your CPU needs additional time just to decompress them. I can give you literally dozens of reasons why an add-on will slow Firefox down. If you’re a web developer, I highly recommend “Performance Best Practices in Extensions” which details all the possible causes and how you—as a developer—can prevent this from happening.
No matter what the reason, this is a massive performance problem you need to solve. Need proof? Here’s a quick test:
As you can see in the screenshot above, I installed the following three add-ons: Personas Plus, Firebug, and FoxyTunes, all known to be “heavier” add-ons. I checked the startup time of Firefox before and after installation, and was frankly quite surprised by the performance difference:
That’s four times longer than normal. Opening up a browser tab also took slightly longer than normal and there was a noticeable delay of about 0.5 seconds.
Search and destroy: Finding slow add-ons
Mozilla dedicated an entire site to listing the current “Top 9″ low-performance add-ons. You can check it out right here.
To check for add-ons in Firefox, click on the orange “Firefox” button in the top left corner and go to “Add-ons.” Then go over to the “Extensions” category. This brings up a list of all plug-ins that are currently installed. Here’s an example:
If you find one of the Top 9 in your list, then you’ll probably want to disable it and then (if you really need a certain functionality), find a replacement. If it’s not on the list or if you’re still experiencing performance problems, I recommend evaluating each and every add-on. Make a decision—do you really need add-on “X” on a daily basis or even at all? Disable the plug-ins and see if Firefox 4 loads and performs quicker than before.