amavis before queue scanning

Hi,
I'd like to prefilter the Mails with spamassassin and reject them before they get queued.
The only thing I'm not shure is the perfomance usage of this method.
I only read, that you should use this method on low traffic servers only.

My question is, when is a server a low traffic server?
Are somewhere examples?
I don't want to tie down my server.

Thanks Niko

 

How many emails does your server process each day? What are the hardware specs of your server?

 

The server is a 2,5Ghz Quad Core, but the ISPconfig server is a Xen guest with 2 Vcpus and 1 Gb Ram at the moment (could be increased)

At the moment I have 4 Msgs/min avg and up to 70 Msgs/min peaks (Mailgraph stat.)

 

I'd say this is a low-traffic mail server (at 4 messages per minute).