I ran a few tests on my website at webpagetest.org and while the Time to First Byte is under 200ms, it seems that in all tests I have run in different browsers at different locations, the page is presented to the screen much later after the first HTML page has been completely downloaded.
I ran a test in firefox from New York using their native connection and it shows that rendering starts at 600 ms yet the first downloadable byte (TTFB) is ready as of 100 ms:
I then proceeded to try chrome from the same computer with other settings the same. TTFB is roughly the same however the rendering starts at 350 ms:
I decide then to try IE 11 from California with other settings the same. TTFB is a bit longer as expected, yet the rendering refuses to start before 600 ms:
My pages are served gzipped and I flush the buffers between outputting the HTTP headers and outputting the actual webpage data.
I'm gonna look into increasing the compression level but if there is anything else I can do server-side to see the first loaded page right away instead of waiting until the browsers decide when they are good and ready to display it.
Also, if you see the filmstrip view of each test, you'll see my problem dead-on because nothing appears on screen before 500 ms.
I do apologize if this question ends up being placed on-hold, but I feel this is an issue that needs a solution, and I'm sure at least someone else experienced similar results with their websites.