We have a performance problem on our site, and we're digging in to correct some rather basic issues -- we know we have many opportunities to improve performance -- this question is about one, in particular.
Our special case is that we intentionally defer loading of one part of our page that is inherently slow until after the stuff users really wants is up and rendered. But tools like NewRelic, and Google PageSpeed all see this as a slow-loading page -- 5+ seconds.
You can see the case at at pubget.com where we display search results for research papers. We allow users get full article and display either "View" or "Buy" buttons depending on some fairly complicated rules (e.g. if their company/university has a subscription to the journal, but there's a lot more) -- these rules take time to calculate. So we load the search results, and then after the page is displayed, we do an AJAX request to get the View/Buy buttons.
The actual work of figuring out what buttons to display (and where they should link) takes about a second, more or less. It seems like the right thing to do from a user experience standpoint, but I wonder if it affects how users and Google sees our site.
(If you do look at the page, you'll see any number of other equally important things we're doing wrong. I know about these and we're going to fix them.)