Q:  Does the infrastructure page take a really long time to load for you?

A:  Take a look at your open event log entries.  Every open event gets indexed when the page loads.  If you want the page to load faster, simply close as many events as is prudent for your historical needs.

If that fails to help, follow this guide to tune the caching and multi-threading options:

http://wiki.zenoss.org/Zenoss_tuning