> My problem then
> becomes scalability. In a large
> production environment, say upwards of
> 50k users, i can't afford for a spam
> filter solution to drop my CPU resources
> to zero. I can't (literally) afford to
> add 10 more MX servers because my spam
> solution hogs all of the resources.
I understand the need for scalability and faster code would be great. I would however challange the notition that you can't afford 10 more MX servers. I think that it's more like "management does not want to pay for 10 more MX servers."
I don't know your costs, but if you just take some simple numbers regarding the true man-hour costs of spam on your end users you'll get into the millions, or 10's of millions of dollars a year in lost man hours. For example 10 emails a day and 10 seconds an email and 50000 users 10.1 hours a year per employeed which translated to 75 million. This is just an example--and it is huge.
If this is true, you have the money, your organization just lacks the will.
I bring this up because I work for a company of similar size, and I constantly see IT saying "too expensive"... but at the same time being happy to push much larger costs on the buget of others due to inaction or stupid policies. I don't know if your org is like that, but mine certainly is.