I've been using Firefox 2 and 3 on Linux (OpenSuse and Ubuntu) for over a year now on different machines with different video adapters, and I can confirm it is

I've been using Firefox 2 and 3 on Linux (OpenSuse and Ubuntu) for over a year now on different machines with different video adapters, and I can confirm it is definitely the slowest browser I've ever used. I disabled all the unnecessary addons, but still it takes a long time to start FF, it eats memory and works slow with js. I can't switch, because it would be more inconvenient to use Opera than getting used to slowness of FF. So I hope this is going to be fixed in future.