Reducing the number of pre-forked processes shouldn't matter that much (at least with Apache). Your kernel implements copy-on-write when forking processes for

Reducing the number of pre-forked processes shouldn't matter that much (at least with Apache). Your kernel implements copy-on-write when forking processes for all the memory that needs to be duplicated, so it doesn't actually use n times the memory, where n is the amount used by a single process -- in my experience web servers usually don't change much of the memory while serving content. Spamassassin might do this differently though and I suspect child processes are more likely to use all the reported memory.