I think I figured it out. Hopefully this will help anyone out with a similar issue. Thanks to shmem I started looking at the connection between spampd and Exchange. It turns out that Exchange defaults to only allowing 20 emails per connections, while Net::Server::PreForkSimple defaults to 1000 requests per connection. So after the first 20 messages per child each child was failing 980 times before restarting to then start accepting mail agian. At least that's what appears to be happening I reduced the Net::Server::PreForkSimple to only doing 5 requests per child and boosted exchange to all 50 and we'll see what happens. If it works then I can fine tune the two closer to each others settings to hopefully get some more performance out if it. Here's crossing my fingers and toes!