I've been with my ISP (IdNet) for a few months and have been getting some good speeds, but in the last week the speed has dramatically decreased (from 15 Mbps+ to around 0.2 Mbps). This happens at all times of day, not just peak periods.

Obviously I've done all I can to isolate problems my end - only one PC is connected to the router (via ethernet cable) and no other background programs are using the network etc.

I've raised the issue with the ISP and they've suggested trying a new ADSL filter to see if that is casuing the problem, but I thought it would also be good to get the opinion of superuser on possible causes or other troubleshooting I can do.

Here are the juicy stats :)

My router (Netgear DGN1000) reports:

                   Downstream Upstream 
Connection Speed   17602 kbps 1062 kbps 
Line Attenuation    17.9 db    8.6 db 
Noise Margin         6.0 db    6.1 db 

I used RouterStats and it seems to show those figures stay fairly consistent all the time

I ran the BT speedtest and it reported:

• download speed of 164 kbps, out of a max achievable of 21000 kbps
• upload speed of 859 kbps, out of 1048 kbps
• DSL connection rate 17719 kbps down and 1048 kbps up
• IP Profile of 15000 kbps

Is there any more troubleshooting I can do? Does this look like a problem with my equipment / wiring or with BT's line?

Any advice would be great :)