I have Mandrill as SMTP to send emails and my good reputation allows me to send almost 100 000 msgs/hr.
Problem is, although I have my phplist setup to process 5000 msgs each 3600 seconds, it’s only processing an average os 1800msgs/hr.
I have talked with my host provider and they told me that they have increased the SMTP sending to 12500msgs/hr, and that it would influenciate the internal and remote sending so the process should now work just fine.
The thing is, everything is still the same and phplist keeps processing only an average of 1800msgs/hr anyway.
I have a huge mailing list and it’s taking days to process all this, which makes no sense since I have a good reputation in Mandrill and I am allowed to send almost 100 000msgs/hr.
MAX_PROCESS_MESSAGE refers to the maximum number of campaigns that phplist will handle, not the number of emails, so there is no benefit in changing that.
Some of the other configurations are inconsistent.
A batch size of 5000 with a throttle of 1s will take more than 5000s to send, so having a batch period of 3600 is inconsistent.
I suggest not using batch processing but only a throttle value to control the rate of sending.
And use a cron job for sending, do not do it through the browser.
See this other related topic Some advice for correct configuration of sending rate
If you enable verbose in config.php then there will be more output in the event log about each email that is sent. In particular it should show the time taken to send each email.
Mandrill claims to have the ability to send at high speeds, but that’s very dependent on the filesize of the email, the processing power of your server, and how fast your server can deliver them to the MailChimp system.
I use Mandrill for a couple of my phpLlist systems, and setting my phpList to send at 10,000 an hour only gets me about 4000 an hour going through Mandrill. Mandrill lets me send at 245,000 emails per hour… so it’s something else that’s the limiting factor.
Actually, I do believe that slow and steady is better than stop, fast, stop… the deliverability is better too…
Also, if I got 1 inquiry per 1000 emails I send, and I could send at 245,000 /hr, that would be a product inquiry every 15 seconds… 245/hr…