Very slow loading time

I love this plugin for so many reasons BUT… the page load time is impossibly slow. I’ve tried disabling all plugins and using the default WP themes, but it makes no difference. Page load speed varies from several seconds to as many as 30 seconds – especially on months that haven’t yet been viewed. Does the number of events affect the load time? I have different events occurring on the majority of calendar days. The calendar grid loads quickly, but the events themselves are the slow loaders.

Thanks.

http://wordpress.org/plugins/event-organiser/