Hi aNoori. How are you doing your speed test? Wired usually produces a better result.
Regardless of this the sync rate will always be higher than the speed test
Mine shows a sync of 73999 and a WiFi speed of 63000
It is wired directly to the router. The speed test is both from Google and Talk talk.
I had a lot problem with my line and had 3 engineer's visit to sort it. About a month ago the router speed (Sync) was 28 Mbps and the speed test showed it as 14Mbps. At the end somebody changed some of my line parameters and the download speed went up to about the same as the sync speed. Now after one month the sync speed has gone up to 38Mbps as the line has settled with the new router and external line, but the download speed has not changed. That is why I think something needs to be changed (optimised) again.