Anything more than a few minutes is too long. 15-20 is definitely a problem, but it may not be Ultima that is the problem.
If you are using the SmarterMail webmail interface (and not a client like Outlook), then you might need to adjust the amount of time the Inbox is automatically refreshed so that it shows you new emails.
To do this, go to Settings > My Settings > Webmail. Change the "Auto Refresh Rate" to 1 minute. This is the equivalent of automatically checking for new mail every X minutes, so if this is currently set to 15 minutes, then that would probably explain the apparent delay. Set it to 1 minute and try again.
William Eaton, MCSE
iTech Computer Solutions, LLC
www.itechcs.com