Help: Improving qmail's performance under Gentoo

[LRdM]

I recently switched my RedHat server over to Gentoo. Along with acting as a router and dhcp server, it also served as an SMTP outgoing mail server for local workstations. I switched the system over to Gentoo with ease but ran into a problem when I finished my installation of qmail. Workstations sending e-mails with attachments via the SMTP server would take a long time to have their outgoing mail processed by the SMTP server, thus hanging their clients or even leading to a timeout because the SMTP server does not send back a finished signal to the workstation. Attachment-less e-mails have had no problems. I hadn't had this problem before when the system was running RedHat and less programs are running on the server now under Gentoo than when it was under RedHat. I've narrowed down the bottleneck to definately be the server. The only significant change has been the fact that it is no longer RedHat but Gentoo. Theres 512 ram which has been more than enough. I used both LWQ installation instructions and the qmail ebuild but still am having this issue. There are no custom patches/add-ons running with qmail, it's vanilla. Does anyone have any tips on how I can narrow down the problem, tracing and debugging qmail for this type of problem has proven difficult for me. Or perhaps a few ideas may come to mind that may remedy this.

Disclosue: This is nothing against Gentoo at all. I've switched over to Gentoo on all of my machines. I am simply trying to overcome this issue and have been able to determine the only siginificant change on the machine to be the new OS. I love Gentoo, so I don't take this as anything against it.