In Settings -> Email Templates you have the possibility to specify how many mails should be sent out during every cron execution. The smaller the number the less your server load.
40 mails are ok for your server load, you can even specify 50 or 60.
The original complaint from you was that you were having an issue, and I tried to explain that this is really not an issue.
That is the cron results which I receive every 10min
- Start email send -
Total queued emails: 338
Ready for send: 40
Processed emails: 0
Processed emails with errors: 0
Do you recon it is the server load, because I am only sending 40 mails per batch?
The original complaint from you was that you were having an issue, and I tried to explain that this is really not an issue.