Netware 5.1, client 4.9, Acer altos 1200, 1gb RAM

When I use Windows explorer and select properties on a network drive, the
Netware server utilisation skyrocket from about 1% to 50% or more. Users
noticed that response is very slow.

This not only last the duration of minutes while the drive scan is going
on, but even when I exit from Explorer. Why?