Spamd startup options - "-d -q -m 50 -x -- siteconfigpath=/etc/mail/spamassassin -i xxx.xxx.xxx.xxx -A xxx.xxx.xxx. -u spamd"
There's a disconnect between the spamd man page and what the error log reports. What you're looking to change is the -m option in your startup. The man page lists that option's long name as "--max-children", though the logs refer to it as "--max-client".
You might want to run a few messages through in debug mode to see what's causing the bottleneck. 50 children should be plenty for that many messages, unless your mail traffic is incredibly bursty. I'll bet some step in the checking process is tying up the spamd children for longer than necessary.
