In the last few weeks, I'm seeing more people complaining about dramatic performance problems. I'm not talking about excess memory usage or a small slowdown in launch time or page loading time, but a serious degradation in performance. One report I just read was a user complaining that it took Firefox 2 almost 30 seconds to launch on his machine while Firefox 1.5 used to start in just a couple of seconds. Another report was of a machine hanging any time the user tried to open more than a few tabs at once.
I've experienced some pretty dramatic problems with Firefox 2 and 3 builds hanging really bad when I tried to open a group of tabs with more than about 6 tabs. Just recently I discovered that Firebug causing some of my problems. Apparently I'd set Firebug to be active on every page and so as I moved around the web, Firefox+Firebug was doing a lot of extra work. Disabling Firebug for everything except my blog where I use it cured me of my major performance issues.
This is the third or forth time that an extension has been the root of my Firefox woes and I suspect I'm not alone.
So, I'd like to do an experiment here. If you want to participate, here are the instructions:
1. List all of your installed extensions.
2. List out your hardware, OS version, and Firefox version.
3. Post your cold start-up time for Firefox - this means after a reboot, when the system is fully loaded and no other applications are running start Firefox and measure the number of seconds it takes to start loading the first webpage.
4. Post your warm start-up time. This means the time it takes to start Firefox after it's been shut down at least once.
5. Post the time it takes to load this set of pages in tabs (just load them as a tab group a few times and come up with an average time it takes to see the last tab's spinner stop: www.yahoo.com, www.cnn.com, gizmodo.com, www.myspace.com, and www.msn.com) or come up with your own set of tabs to measure.
6. Repeat steps 3, 4 and 5 running with all of your extensions disabled and post the results.
Of course, as with all clock on the wall tests, it's not critical that your measurements be exact. The goal here is to see if there are any dramatic performance issues running with and without your extensions.
Here are my results with all of my extensions fully enabled:
1. I have the latest versions of CoComment, Full Page Zoom, Nightly Tester Tools, and DOM Inspector.
2. I'm running a first generation MacBook Pro, 2Ghz Core Duo, 2GB RAM, with OSX 10.4.10. I'm yesterday's Firefox 3 nightly build.
3. Cold start averages about 8 seconds.
4. Warm start is between 1 and 2 seconds.
5. Tab group load takes an average of 8 seconds.
6. With my extensions disabled, my cold start is 6 seconds, my warm start feels a tiny bit faster, around 1 second and the tab group loads in about the same 8 seconds.
So, for me, the extensions seem to have a small impact on startup time but no impact on page loading time for this group of pages.
What's your experience? And if you can do more thorough tests, please do. I just provided these as guidance to try to learn something about extension impact on performance.
Photo by Flickr user pandiyan and used under a Creative Commons license.