Maybe it's just faster because none of your extensions are running? The ones you listed sound like they probably use lots of CPU time and memory, and if they are disabled I'm sure FF runs much faster / lighter.

I can't comment on how much the extensions might have affected things, but startup time was significantly improved: https://wiki.mozilla.org/Firefox/Sprints/Startup_Time_Improv...

Same reason.

You can set `extensions.checkCompatibility.4.0b` to false in `about:config`.

try this https://addons.mozilla.org/en-US/firefox/addon/15003/

I agree definitly alot faster, but it's a shame almost no plugins work except for extensions/addons/plugins found at http://mozillalabs.com/

But just give it a little time, firefox 4 is definitly worth the wait.

Extensions normally don't work with new versions mostly because of the em:maxVersion requirement in the install.rdf file all extensions use for their metadata. You can probably unzip your favorite extension, modify the file, zip it back up and it might work just fine.