My sync was about 60 when 55 57
It was 47 in spring but i got 31.5 i had a wwp and a static ip thats bad if the isp forgets to keep an eye on it
Sync was 47 until cab copper move, then as i put at the time 40
Now its 37
I know about sync and real world overheads i e been using, fixing, building computers since 1985
The speed test available site is dynamic as just monts ago it said 63 max, min 47 if i remember. Not worth a thing as its a snap in time
When the cab was moved it said max 28d 0.5u then went on to explain that was a good rate for my line
Then the guy next dorrs said adsl only even though he had vdsl
The hand back was 47 on the isp AND thats dynamic
No matter what the sync was it never went over 31.5 pn found a 31.5 wpp and removed it but it was too late, it was syncing at about 40 so got 36 rw
We feed copper to the rest and a guy i know at the end run gets 50 ish
Hes a youtuber so may have a business line not sure