Reducing memory usage on Linux VPS box running ISPconfig

I'm currently running an ISPConfig3 setup following on a Linode VPS with 1.5GB RAM, and it's working pretty good.
However, I'd like to optimise it with an aim of running it on a 1GB linode.
I only have about half a dozen websites with associated email accounts, etc. The websites are mainly Wordpress ones.

If I reboot the node and leave it for a few minutes to settle down, it takes about 1GB RAM, but this often rises to around 1.3 - 1.4GB in use.

Edit: current RAM usage:

Code:

---

Name                Count        CPU        Memory
amavis                3        0%        280 MB
clamd                1        0%        245 MB
apache2                11        0.01%        152 MB
mysqld                1        0.14%        48 MB

---

Looking at the memory usage, the greediest one seems to be ClamAV running with Amavis-new for scanning email: they seem to eat up to around 400MB between them which seems rather excessivee to me!

So I'm trying to decide what my options are and would really appreciate your thoughts / recommendations.
Do I:
- Remove all av / amavis packages to free up the ram (but take a risk on virused an wormed emails?)
- Keep what I have but "tune" it. If so, are there many parameters to reduce RAM usage?
- Change from ClamAV to something else, if so which AV? BTW, ClamAV is currently running as the daemon (clamavd)
- Something else?

So any of you with experience running these kind of systems with some ideas?

Thanks in advance,
Xav

No experience in your specific situation, but is it worth switching out amavisd-new for amavisd-lite?

... reinstall as 32-bit? Makes me ill to think about, but it would reduce RAM usage