Yes, nothing to do with the ISP.

There are many variables in these lines. Look at the stats of my short line ...

Data rate:
20.00 Mbps / 80.00 Mbps
Maximum data rate:
36041 / 105629
Noise margin:
23.3 dB / 12.3 dB
Line attenuation:
9.4 dB

My theoretical max is higher than the others shown, yet the attenuation is different again. An accurate measurement with a TDR from NTE to DSLAM showed 220 m.

All these stats are just interpretations of the various inputs, they are indicators rather than gospel truths.

As Zarjaz says, the figures are indicators.

There are many, many factors which can influence the various factors: Diameter/gauge of the wire, quality of the copper, aluminium or even steel wire for some parts, the component quality in the modem and how close they are to ideal, chip-set, cross talk from other users, cable twist rate (or none), external noise from many sources including radio transmissions or domestic and industrial equipment, and quite a few more.

In reply to a post by asrab:

may be its the service provider or crosstalk

Crosstalk can be negligible or huge. In theory, it can steal more than half of your speed.

FEC and interleaving settings make a difference, with the worst case maybe stealing 20% of your speed.

In reply to a post by asrab:

In reply to a post by lee111s:

Nothing to do with the ISP.

Are you sure ? My neighbour on the left has Sky, thier Sync speed is higher than mine however my neighbour straight in front of me has Plusnet and is worse than mine,

Yes, as you�ve been told it�s nothing to do with the ISP. The DSLAM for FTTC (in the cabinet) is owned and managed by Openreach. It works different to ASDL based broadband.