Memory usage and ZD2 stop responding

[BSF]

I normally leave ZD2 minimized and check my e-mails whenever the yellow envelope pops up in notification area of the taskbar of Win Vista.
I rarely shutdown Win, but rather hibernate.
The following happens quite often:
1. In any situation:
a. A quite huge chunk of the the system memory is taken by the zdclient.exe process (often about 1GB!!!!!!!!!).
b. From times to times, ZD just stops working and an error message informs that prism stopped working and I have close and to restart Zimbra.

2. Upon restoring the system from hibernation, the computer is often unbearably slow and only when I kill the zdclient.exe and zdesktop.exe processes it comes back to life with decent performance!

System:
Windows Vista Business SP2 32 bit
Intel Core2 CPU T7200 2x2.00 GHz
RAM: 2GB
Sony Vaio VGN-SZ5XN

Thanks!

[apatosaur.9]

I am in the process of migrating an organization from Exchange 2003 on SBS2003 to Zimbra 7 NE. (20 users)

Two things are a problem

1) the amount of RAM that zdclient or webUI uses. about 2 x (or more) as compared to MS Outlook 2003: Users have large mailboxes >3Gigs with thousands of emails in their inboxes. Zimbra desktop uses upwards of 170MB of memory. Switching off Zimbra Desktop and using browser interface in IE7/8 or Firefox4 causes the browser memory useage to climb to the same. The desktop machines in use are WinXP sp2 with only 512MB ram.

A) Is this because of the large inboxes?
B) What is normal RAM usage of zdclient apps.

2) as per Any advice on Zimbra client speed increases? - Spiceworks Community, most users are happy with the performance of zimbra, but one user reports:

deleing an email in ZIMBRA takes between 4 and 6 seconds for each email. i delete around 500 emails a day so 500 times 6 seconds = 1 hour each day simply waiting for an email to be deleted...
As things stand ZIMBRA appears to be a ... a lot slower than outlook ever was

This user is using Firefox and/or zimbra desktop client, and has an inbox with 20,000 unread messages. Is there anything that can be done about this perceived performance issue?