slow firefox under linux

The speed firefox handles multiple tabs, popup-windows  and the content itself is much better under vista than in (gtk-world) linux. Kind of frustration. But there is swiftfox, an optimized version of firefox for linux (and its different architectures) and I should have found this thing much earlier!

Update

It seems as if there is no satisfying method of getting flash-sound running under a 64 bit system … :/