Mailscanner mqueuein trouble

[Marcos Sobral]

Hi, I need a hand.
I´m actually having problems with Mailscaner. I have around 150,000 
emails each day.
I´m working with 3 smtps servers each one with sendmail and mailscanner, 
the servers are an Atlhlon 2000 (512mb ram), a P4 2.4 (1Gb ram) a P4 2.8 
(512ram). I use pen loadbalancer to balance them
Both P4 have 2 harddrives (ide 7200rpm) one for the system other for de 
mqueues dirs, the Atlhon has only one hard disk.
And after trying tunning Mailscaner (like using tmpfs for de incoming 
dir), instead of all my efforts the mqueue.in increases creating delays 
of 20 to 60 minutes.
If someone had problems of this kind I would like if he could give me 
some advices.
Also I would like to know which hardware do you recommend for a diary 
traffic of around 300,000 emails.

Thanks!

Marcos.