Since GMAIL changed its user interface from version 1.0 to 2.0, there were a lot of complaints from all over the world, from users of different browsers (Firefox, IE, Safari, Opera, etc..), that their GMAIL works very and very slow.
PROBLEM:
The first and the most frequent slow behavior is discovered by gmail users during login in to their accounts from http://www.gmail.com. This is mostly due to the fact that by default they are using a 2.0 version of Gmail’s User Interface (UI).
It seems that the 2.0 UI was not well “stress tested” and hence it is far from being as scalable as its previous, proven to scale, 1.0 version.
SOLUTION:
Since GMAIL code belongs to GOOGLE and they are actively working on it, it would make sense to trust them with fixing gmail’s 2.0 UI in near future – it is GOOGLE, and it just makes sense to trust them, at least for now it does.
However until that moment comes, when GMAIL 2.0 UI is fixed, here is a quick workaround for the “slow gmail” problem: Instead of going to http://www.gmail.com which brings up 2.0 UI, go to https://mail.google.com/mail/?ui=1 which explicitly tells gmail to use 1.0 version of UI. This will work as fast as before, and will get you back on track with loving gmail. :)
Good luck!