I do not really believe that. I have a site which is served way faster than it's Amp version. Obviously Google never really care to check whether original page is faster than AMP. Yes I have numbers. AMP version loads about 400ms. While the original was about 300ms. Almost certain for all pages.
That was likely a singular measurement, likely from your notebook. A user at some other location might very much disagree, unless your site has a CDN as extensive as Google.
"Pinboard founder Maciej Cegłowski already recreated the Google AMP demo page without the Google AMP JavaScript and, unsurprisingly, it's faster than Google's version."
