According to the "About" page of Google PageSpeed Insights the test measures:
- time to above-the-fold load: Elapsed time from the moment a user requests a new page and to the moment the above-the-fold content is rendered by the browser.
- time to full page load: Elapsed time from the moment a user requests a new page to the moment the page is fully rendered by the browser.
I'm not a native English speaker, so the "above-the-fold" load sounds strange to me, especially as the same "above-the-fold" is used even in the definition and nothing else is described in there.
So, what's meant by the special "above-the-fold content" i.e. what files and/or what elements of the page are in this category and how is it different from the full page load time?