I also experience intermittent slow response. I'm usually logged-on in the early AM, so I suspect it could be maintenance scripts running on the server when it happens then. But I've also had slow response times in the afternoon and evening, and that may be due to an increase in users performing searches. I was on another XenForo forum and the hosting company suggested it could be search function usage. To test that theory the Admin disabled searches and the problem disappeared. But it could just as easily be a network issue.
It's a little slow to respond here too. The number of members / guests isn't displayed so you can't get an idea of traffic. And looking at the current visitor list is too slow to click through the pages.