If I'm looking at the right site, it looks like the second page of your event registration has a consistent 60 second delay added on top of the usual page generation times, and that the delay is introduced before the user is asked for payment.
Unless your payment processor requires communication before the transaction, this suggests that the issue is within CiviCRM or your hosting environment.
An additional 60 or 120 second delay is often a timeout, for example when a webserver attempts to get reverse DNS during the request and fails. However there's no way to be sure without looking under the hood, so I'll provide general advice on how to proceed also :)
- Use tools like http://www.webpagetest.org or http://fpt.pingdom.com to ensure your site performs well generally - enter the URL of your registration pages and make sure the entire page is delivered to the visitor within a few seconds.
- Ensure your hosting environment is capable of delivering your content in a reasonable timeframe.
- Disable configurations which add to request time, eg reverse DNS lookups.
I suspect this issue is not related to your payment processor at all.