I can see sjvn chortling over there, reading this post. I can hear him thinking, "I'll show you how to speed up Firefox. It's simple: run Chrome."
See also: Chrome: The people’s Web browser choice
He's probably right, but there are things about Chrome that annoy me, and I haven't taken the time to really get to know Chrome and make it a friend. Firefox is still my daily driver.
The Firefox we had running on our media PC had slowed to an unbearable, unusable crawl. Yes, I can hear some of you out there. That's how Firefox usually is. Funny.
The point is, it was moderately usable last week and completely unbearable this week. The further point is, I found a way to speed it up. Now, you want to settle down over there for a minute and listen? This might actually help you.
Diagnosing the problem
My wife and I share the media PC, which we use when watching the big screen from the couch, so we each have a Firefox profile. When either of us launches Firefox, we get a simple dialog asking us to choose our profile. After a day or so struggling with a completely bogged down Firefox, I realized my wife hadn't been complaining.
I launched her profile (her background is flowers, mine is a more dignified gray), took Firefox to my usual morning reading sites (ZDNet, TechMeme, Drudge, Google News, etc.) and found that using her profile, I didn't experience the bogged-down effect I did when running my profile. Sure, pages slowed whenever anyone ran some big third party ads or other obnoxious detritus of the modern age, but in general, her Firefox ran relatively well.
So I did what I recommend to others to do. I turned off browser extensions in my profile. No difference. My Firefox was still dog slow.
Finally, I decided to try the nuclear option. I created an entirely new profile.
Once I launched into that new profile, everything ran far better. I could visit my morning reading sites and they actually loaded (they were normal-Firefox-slow, but not unbearable-Firefox-slow).
Next, rather than copying my extensions over from the old profile, I downloaded them from the Firefox add-ons page. Firefox performance was still good.
I realized later that while I'd disabled and tested extensions many times, my actual Firefox profile was probably a good three years old. It's been in continuous use since Firefox 3.5 or 3.6. Sure, I'd updated my extensions, deleted some, and otherwise done Firefox maintenance, but I've never completely started fresh, with a completely fresh profile.
And that was the ticket. So if you want a quick-and-dirty way to run Firefox faster, create a blank profile, don't copy anything over from the older profile (I use XMarks for bookmarks, so I just downloaded a fresh set from the server), and download your extensions fresh as well.
Browsing speed will improve from intolerable to moderately tolerable. And that's about all you can ask from Firefox these days.