Contact Category update Slow

[Bucklebery]

We are using SBS 2003. If I select say 8 contacts and choose a categry to
add to all contacts - the update is painfully slow - say 22 seconds. The
screen goes white and eventually it comes back - done. If I do 100
contacts - I can make a cup of tea. Why is this so slow? How can I speed it
up.

Thanks for your speedy reply!!

Cheers

Ian