Nice site thought you should start optimize for speed 1.4 seconds to generate content is too much..
I am under 500ms:
Not using full page cache, but my own cache solution, currently deactivated for tested domain..
I also switched from jquery to zepto for front end, it is much more mobile friendly (less javascript parsing on mobile devices), and using my own HTTP2 push module for css and js resources.. CloudFlare is great for lightening your server among other things... when configured correctly..