I've been having a PM conversation with Cris about my ADSL connection. Since the Beeb had launched their HD content on iPlayer is was a little miffed that I couldn't watch it.

Originally my modem was connected in the study on the end of the extension. It's connection stats looked like this:

Uptime: 0 days, 4:01:05
DSL Type: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 640 / 1,792
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 2.00
Output Power (Up/Down) [dBm]: 12.0 / 17.5
Line Attenuation (Up/Down) [dB]: 29.0 / 47.0
SN Margin (Up/Down) [dB]: 13.0 / 11.5
Vendor ID (Local/Remote): TMMB / GSPN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 459 / 0
FEC Errors (Up/Down): 0 / 1,220,440
CRC Errors (Up/Down): 0 / 22,860
HEC Errors (Up/Down): 0 / 19,335

Following Cris' advice I moved the modem downstairs, put it on a 3 meter extension and disconnected the circuit upstairs. Now the stats look like this:

Uptime: 1 day, 1:21:04
DSL Type: G.992.1 annex A
Bandwidth (Up/Down) [kbps/kbps]: 640 / 4.640
Data Transferred (Sent/Received) [kB/kB]: 0,00 / 0,00
Output Power (Up/Down) [dBm]: 11,5 / 19,5
Line Attenuation (Up/Down) [dB]: 27,0 / 46,0
SN Margin (Up/Down) [dB]: 14,0 / 11,5
Vendor ID (Local/Remote): TMMB / GSPN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 0 / 0
FEC Errors (Up/Down): 95 / 21.192
CRC Errors (Up/Down): 95 / 33
HEC Errors (Up/Down): 45 / 28

As you can see from the figures, not much is changing, other than a 'huge' jump in line speed (IMHO). You should definitely check your extension wiring Roger.