Super User is a question and answer site for computer enthusiasts and power users. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I'm running Firefox 3.0.14 32-bit on Ubuntu 9.10 32-bit.

It's much slower than in Windows XP on the same machine.

Does anyone know why?

Also, what's a possible way to improve the performance?

(Please list optimizations as their own answer, so they can be rated independently.)

share|improve this question
I am seeing the same thing. The only thing I've seen as a slight improvement is disabling addons, but that hasn't helped significantly enough to merit losing echofon and tabmixplus. – Sakamoto Kazuma Oct 23 '09 at 0:50
Actually, my experience is just the opposite. On my home machine (same config as yours), firefox is quite perky. On my Windows XP machine at work, even though it has twice the memory and nothing running or mounted filestystems that might explain sluggish performance, Firefox takes much longer than IE 6 to appear. I have considered switching to opera, but have stayed with firefox mostly out of laziness - the performance on my XP box sucks. I have no plugins other than what comes configured by default in both locations. – DaveParillo Oct 23 '09 at 4:03
up vote 4 down vote accepted

One of the cited reasons is that Linux version of Firefox is not built using PGO. PGO stands for Profile Guided Optimization. Windows version of Firefox is built on Visual C++ with PGO

IIRC Even Mozilla does not provide PGO compiled binaries for Linux. They have given a HOWTO for building Firefox with PGO, but how many of us can really do that?

If you want to get PGO compiled binaries, check Ted's PGO builds

OTOH Benchmarks show that even Windows Firefox over wine beats native Linux Firefox. If you are really unhappy, then use Chrome. Trust me, it is blazing fast.

There is a risk with PGO, since if the data provided is not proper, the performance of the final build is even worse than what it would be without PGO. Quoting from Wikipedia

The caveat, however, is that the sample of data fed to the program during the profiling stage must be statistically representative of the typical usage scenarios; otherwise, profile-guided feedback has the potential of harming the overall performance of the final build instead of improving it.

share|improve this answer
+1 for Chrome, and it costs fewer memory for heavy and long-time users. – CyberSnoopy Oct 25 '09 at 0:56

If Ubuntu 9.10 is fully updated Firefox 3.5 should be the default browser. It doesn't make sense to worry about an old release. Version 3.5 has an improved JavaScript engine and is much faster. Also, unlike windows builds, linux builds are normally not compiled with PGO.

You should try a 3.5 build. Also, you can try Chromium, that stacks up very well with other browsers in terms of performance.

share|improve this answer

Have you tried basic troubleshooting? Installing a modern (3.5) build?

share|improve this answer

On my netbook I noticed a performance hit was due to the fact the video card just sucked. It was a generic built in Intel chip. On my desktop which has Nvidia 9800, Firefox flies under Linux.

My observation anyways.

share|improve this answer
this. even worse is if the machine is old and the video card isn't well-supported under Linux. i tried to repurpose my ThinkPad T40p from school with Ubuntu, but even the scrolling of Firefox was enough to make me go back to XP. (For the record, Vista and Win7 didn't fare much better. It seems only XP had reasonable drivers.) – Jewel S Nov 3 '09 at 4:26
Intel chipsets were bad in Linux until Ubuntu 9.10--if OP is running 3.0 it's obviously not using Ubuntu 9.10 as that ships with FF 3.5. – Broam Nov 27 '09 at 15:41

Disable hyper-threading in the bios. Although its counter-intuitive, that has done more to improve my firefox 3.5 /ubuntu 9.10 performance than anything I've tried. Essentially, it fixed it.

share|improve this answer

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .