I just tried your site and the report was
Generated in 0.012 seconds in which 0.002 seconds were spent on a total of 5 queries.
Looks good to me,
What Rick is referring to is not a problem with your host provider where your board is located at but your ISP you use to browse the web. If you try a ping or tracert test you will see that sometimes it is quite slow or very fast. This has nothing to do with your hosts server sometimes but just how fast your personal connection is.
So when you open your browser and type
www.yourforum.com you send a request for info. The host server builds the page and then downloads it back to your browser. If the host is fine which it sounds like it is but your connection is slow it is going to take a while before your browser receives the info and builds the page.
If that is indeed the case then you would need to call the internet provider at your home to see if there are issues.
Also if you trace or ping you will notice that it not only hops from your provider to your web host but it may go through several other connections before it gets there. Anyone of those other connections could be the problem also.