Just tried plugging the mouse directly into my new hub - the performance slowed to it's previous state. Then, when I reconnected the mouse to the Icekey, the performance was the same. After restarting, it was back to superfast again.
It's nice to have some more speed on the mouse, but it seems very erratic. I seem to have an old problem back again from 10.2 - the mouse resets it's speed when unplugged/replugged.
There is celarly an issue with the Icekey, perhaps via the particular hub I got. I'll contact Macally.
Not much luck with this new gear - my new mouse from Macmice was faulty (and showed similiar speed issues through the Icekey).
Thanks