After accidently and violently upgrading to the latest debian stable I thought I'd give a different pop and imap server a go. I tried dovecot because it handles ssl/tls itself removing the need for stunnel.

Downloading pop mail from 15 different accounts at the same time with pop over ssl used to take between 500 to 2000 IO tokens, now it takes less than 200. It's also faster.

Using squirrelmail to load an account with 50 meg of mail in around 1200 messages used to use around 4000 io tokens and take around 10 seconds, now it takes about 2 seconds and uses around 75 io tokens. No 4000 to 75 isn't a typing mistake!

I was so impressed I thought I'd post about it!

What pop/imap system were you using previously ?

uw-imap and popa3d. Stunnel for the ssl.
I only ever used imap as a backend for squirrelmail.