What you can infer from such testing is that the server is not writing any response for a while, and then quickly writing all the response. There could be two reasons - the server may be busy doing some blocking activity, or the server or some intermediary is buffering all the response in memory and emitting it when the complete response is available. Experience tells me that it is usually the former. I'm the author of this post.

Well said. Pages that start with the view like PHP and JSP fare better than most dumb MVC frameworks.

Putting a cache in front is not a solution to all performance problems!