ZD works so slow?

[grey]

Just now install ZD 1.0.3
Windows XP SP2
CPU - Celeron 2,66 presscot
2gb ram
antivirus - disabled.
Java 1.6.0_16

then i going from "inbox" folder to "drafts", occurs delay... At delay moment task manager shows:
50% cpu used by zdclient.exe
and zdclient.exe + zimbradesktop use 36 + 138mb ram.

1)This normal for ZD?
2)How can i raise performance ZD?

p.s. ZD is empty 2-3 inbox messages...