Is my download speed capped?

[#1]

We upgraded from an old Plusnet product to Plusnet Premium in February 2010, allegedly the ‘ADSL 2+ up to 20 Mbps’ service. Nonetheless, our download speed has remained in the range 1.5-3Mbps, just the same as on our old ‘up to 8Mbps’ product, but costing a bit more.
Our line had been subject to quite a lot of line dropouts, resulting in the download speed sometimes going as low as 1.5Mbps. I have now tracked this down to some local intermittent RF interference that not only caused interference on our analogue TV but knocked out the router as well. Our router is located in my home office at the end of a good quality exterrnal extension directly wired into the extension side of our BT box. Having read about the ‘bellwire effect’ (http://www.jarviser.co.uk/jarviser/broadbandspeed.html), I disconnected the bell wires from the extension connection in the BT box. The router sync speed immediately increased from a low of 2800kbps to 4700kbps, and our IP profile to 4000kbps. The line has now been stable for 11days, without any dropouts. However, our download speed has stayed constant at 1.8Mbps. I had expected that the BT software would have increased the download speed accordingly, but sadly it has not. My router reports a download signal to noise ratio of 8-9 and a ’ping’ test says that we have an excellent line quality.
It seems that my download speed has been capped in some way. I cannot understand why and am rather dissatisfied.
Any ideas or similar experiences out there????
Now, the plot thickens. My adjacent neighbours are recently upgraded to ADSL 2+ BT broadband customers who are now seeing download speeds in the range 4.5 -7.0 Mbps. Another friend a few yards away (also upgraded by Plusnet to Premium ‘ADSL 2+ up to 20’ some months ago but with download speeds no better than 3.5Mbps) has just had an e-mail from Plusnet to say that his service is about to become the ‘up to 20’service as a result of BT improvements to our exchange. Why have we been sold a product that does not deliver what it should?

[#2]

Hi Kentmere,
Please can you run a BT Speedtest? This will give everyone some further information as to what's going on.
You can find the BT Speedtest at http://speedtester.bt.com

[#3]

Quote

The line has now been stable for 11days, without any dropouts.

I think that might be why. Let me explain, both BT and PlusNet implement an IP Profile for your connection. As you discovered BT raised your IP profile once your higher synch speed had stabilised, and the PlusNet profile should ( usually within 12-24 hours ) follow the change in the BT profile.
Now for the tricky bit, sometimes the PlusNet profile doesnt follow the BT one ( it relies on the profile change notification from BT's systems ) and here's the crunch, you need to disconnect/reconnect to action the updated PlusNet profile.
You can check your PlusNet profile here https://portal.plus.net/my.html?action=data_transfer_speed if it agrees with the BT profile then you just need to disconnect/reconnect , if not then call CSC and tell them your profile is stuck. 

[#4]

Hi there,
As far as I can tell your profile is 4000, can you run a BT speedtest for me and let me know the results.

[#5]

Thanks for comments.
Mand:
just done BT speedtest - 9.55pm 26-05-2010:
Test1 comprises of Best Effort Test:  -provides background information.
Download Speed
1662 Kbps
 
0 Kbps 7150 Kbps
Max Achievable Speed
Download speedachieved during the test was - 1662 Kbps
For your connection, the acceptable range of speedsis 600-7150 Kbps.
Additional Information:
Your DSL Connection Rate :4720 Kbps(DOWN-STREAM), 444 Kbps(UP-STREAM)
IP Profile for your line is - 4000 Kbps
The throughput of Best Efforts (BE) classes achieved during the test is - 13.72:28.1:58.18 (SBE:NBE:PBE)
These figures represent the ratio while sententiously passing Sub BE, Normal BE and Priority BE marked traffic.
Mand: The above result is typical of what I have been getting throughout the day. Usually is about 1800 kbps at less busy times.
David A

[#6]

That looks like it might be exchange contention, have you checked the status of your exchange? http://usertools.plus.net/exchanges/