I use webpagetest.org to test my website very often.
When I used a couple of remote desktop computers on their site, my TTFB (time to first byte) measures between 1 and 400ms. However, on nearly all mobile tests, from devices from the RealMobile Networks (headspin.io) category, my TTFB measures in at least 1500ms (except for San Francisco which measures at 100ms). My server is located in Quebec and the same one was used with the exact same configuration with no heavy load on the server and I ran each test at least twice.
I understand that there are some variances in the TTFB, but I don't understand if its really true that the TTFB for mobile devices can be significantly that high for a long distance.
I feel like my low income on my mobile site might be due to the high TTFB for mobile devices.
Could it be that I'm using an unreliable tool to test mobile TTFB?
Any suggestions on what I can do to get an accurate TTFB reading from a mobile device to my site so I know where I actually stand?