The DreamHost status page advised that maintenance was scheduled and accomplished for the homiemail-sub5 email cluster on January 2nd. The event is marked (RESOLVED). No resolved here I'm afraid.
While it seems that the change has solved a previous problem I was having with frequent failures to connect to the DH POP3 server, I'm now having a new (and possibly worse) problem.
Email messages are now very slow to download, both via POP3 or IMAP. I'm seeing download speeds from the mail servers of less than 15 kB/s. It most cases it's less than 3 kB/s. A message with no attachment(s) will take a minute or more to download. A message with a 3 MB attachment will take over 10 minutes to download.
I'm having this issue on numerous devices, using different email clients, and with several different Internet connections.
I've opened a trouble ticket and haven't heard back from DH tech support yet. I thought I'd bring this issue up here lest anyone else is seeing the same thing. I'll be surprised if I'm the only one with the problem.
edit: A few hours after I created my trouble ticket and posted this message I heard from DH tech support. They said there had been a misconfiguration on the mail machines and that it had been corrected.
I am indeed finding my email download speed seems back to normal.
Keeping my fingers crossed!