Firefox 4 was a lot faster than Firefox 3.6 in all sorts of ways. Some of those improvements were checked in before Firefox 3.6 was even released. The only re

Firefox 4 was a lot faster than Firefox 3.6 in all sorts of ways. Some of those improvements were checked in before Firefox 3.6 was even released. The only reason it looks like they took a long time to do is because the release cycle for Firefox 4 was long, so you didn't see the improvements until the final release of Firefox 4. So all the release schedule is doing here is getting improvements out to users closer to when the code is written.