Here's some real world stuff. My neighbour gets 76/20 and on my two fibre lines one does 51/18(used to be 72/20) and the other 75/20 and all come from the same pole.
The Openreach engineer's explanation for the difference in speed is that the slower line is probably routed along the main road and down from the top of my road completely ignoring the fact it used to sync at about the same speed as the other which sort of blows his theory out of the water somewhat. His suggestion would make the line length about 1.2km
Who is your isp if i may ask, ive just joined with zen And i want more upload so im thinking of getting another line put in., although some high latency spikes ( no fault of zens network - mainly BT/OR ) everything is ok and with even not being half the speed of my old VM conection its 100% more USEABLE than the Vm conneciton ever was.
I can finally game and use the net at night when im at home.
yeah theres something odd about the whole line setup thing, Somelines more degraded than others maybe ?? Have them lines ever been replaced at all? I dont think mine ever has been replaced. I couldnt see openreach digging up more pavement/ road up for fun when they already have ducting there in the first place for phonelines so as u say it kinda makes the engineers comment seem kinda pointless.
Have you load balanced your 2 lines at home or do you treat them as 2 seperate connections.