It was actually known as the fast option. You have to remember that this was from a time where the alternatives were Eclipse and NetBeans. Lightweight vim/emacs style "text editor" IDE's (maybe except for hardcore configuration heavy plugin collections) hadn't come around yet.
I guess if you compared it to those two, it definitely was faster ("lightning" though, really?). TBH, at the time, for Java I was happily using the likes of jEdit with a bunch of plugins, and for Microsoft stuff I had Visual Studio. Those editors were fast; IDEA had many advantages in comparison, but definitely not speed for me.
