As the title says, when I analyse the websites page load speed in chrome, I can see the wait time or the ttfb is 55ms and total page load time is 1second or less, but when I run the test via https://www.pingdom.com/ or http://gtmetrix.com/or the google speed test tool, the wait time is 1.8 seconds or more and total page load time is 3 seconds or more.

The page is fully cached and the cache has been warmed.

I cant understand why this would happen? the efforts I have made so google would see my site as fast loading will be lost.

Please don't comment about all other optimization tips like gzip and minising css files, I am purely asking about the wait time or ttfb.

Thanks