Okay, slightly odd this.

If you fire up Services and go to Application Downloads one of the links is SMS Accelerator.

It's a 2KB update that makes Messaging work like butter. Seriously. I just installed it and now Messaging is super-nippy (relatively speaking, this is S60).

So... why have this as a random optional update? Seems pretty critical to me, shouldn't it really be in a full-blown software update?

Anyway, whatever they have done in 2KB has made real difference so I'd advise anyone else who finds Messaging on S60 to be sluggish to give it a try.

The mind boggles.