[JoshTriplett]

Do you have any extensions installed?

Have you tried using a fresh profile, just to narrow the possible variables?

If you've checked both of those things, and you can characterize the slowness in the context of specific operations (e.g. what "laggy" means, precisely), then I'd recommend filing a bug and working with the developers to track down the problem. Because that is not normal.

[fmoralesc]

Also, current Firefox has `about:performance`, where you can diagnose what addons and tabs can be slowing down the browser. It's quite neat.

I just refreshed my profile and performance improved immensely.