There are two main metrics for page speed: time to first byte (TTFB) and fully loaded page. The former is the time it takes for the server to send back the first byte of data. It is useful to give you an idea about the server speed but useless about user experience, because the first byte bears no meaningful information for us humans. The time it takes for a site to load fully is more important in that regard, even though it also could be slightly misleading for the simple fact that a certain element might take forever to load. Even without it, though, users are likely to access the information they came for without much of a problem.