The faster you set your cron for the more precise you can be with your sends. That is if you set it to run every minute then your emails will be sent out at the exact time you schedule.
Setting it to 10 minutes means that there could be up to 10 minutes after the time you desire to send and the time it is actually sent.
In the settings page of Interspire Email Marketer you are able to increase and decrease the amount of time that Interspire Email Marketer will allow the cron job to run certain jobs so if you can set it to 1 minute you can then throttle the sending in Interspire Email Marketer so emails are sent out every 1 minute, autoresponders are sent out every 10 minutes and your bounce handling is performed once an hour for instance.
Either way, if you wish to set your cron to 10 minutes that is perfectly fine. It is up to you and your host as to how frequently you want and can have the job triggered.
