in the last days my (up2date) Zimbra Server is very slow. The WebInterface
is low.

The load is always up 2,xx 2,xx 2,xx
On TOP the CPU Usage ist most under 15%
most unter 5 Processes are Running
The Server has 2 XEON 3,4GHz CPUs and 2048 MB Ram.
It host 25 Users...

How can i check, why the server is so low.