It depends which version of Firefox you are talking about, but based upon 4.08Pre which I am currently running -

Load times are fast and javascript speed is very similar, if not better than Chrome [1]

Currently, only the mobile version of Firefox will have tab separation in the form of the electrolysis project for the upcoming version. Plugins do currently run independently of the browser process.

Extensions in Firefox are a lot more powerful; they can slow things down and cause memory leaks.

In the latest prerelease, pages and their plugins do not reload when detached.

[1] http://arewefastyet.com

edit: Disabling the javascript features of firebug allows Firefox to use its jit tracing leading to faster javascript speeds.

It's so strange to hear people say this. I'm running FF 3.6 on Ubuntu 10.04 x64, and its performance is comparable to Chrome. Chrome's a tad faster, but not significantly so, while FF is actually more stable with tons of windows open (~45+). Flash crashes about equally in both (and worse in Opera 10), although not so frequently as to be unusable.

FF is actually so good I switched from Chrome/Chromium to FF a few months ago (mainly for Vimperator though, but the performance differences were marginal enough not to matter). I can't help but wonder if 64bit Linux is FF's optimal platform, with its performance dropping off on Windows and maybe Mac? What OS are you guys running it on?

This isn’t an excuse for your Fx speed problems, but have you tried starting it in safe mode? If you’ve been using the same profile since 1.0 then it’s probably quite unhappy.

http://support.mozilla.com/en-US/kb/Safe+Mode

If that makes things much better for you then you can create a new profile and migrate a few things over. And yeah, Mozilla should really fix this problem.

Well I've been using Firefox since back when it was called phoenix. :P Not that that's even remotely relevant.

Chrome is my default browser but FF 4 is a worthy contender. Using FF 3.5 seems like taking a step back in time, but FF 4 feels very fast, responsive, and is more usable than ever. When it's released it'll put Firefox back in the game.

I'm using ff4b6 right now.

Firefox's page loading speed (especially with ff4b) isn't actually noticeably slower on most sites than Chrome. Until Mr Flash and other plugins come around. That's probably what makes FF feel so horrible right now. Flash video just kills FF performance (just having the video paused in another tab) like nothing else. They seriously need to fix the flash problem. Having flash crash and bringing down my whole browser sucks.

Aside from that, downthemall's problem is the plug in itself. There's definitely something wrong with how the plug in is written, not FF itself. And I believe FF4 tears tabs correctly now.

> Having flash crash and bringing down my whole browser sucks.

haven't OOPPs (out of process plugins) been released since ff3.6?

I thought they were, so now there's a process called plugin-container.exe, I'm guessing one for each different type of plugin, and if that crashes or stalls, FF still goes down (or stalls).