ADSL Connection Speed Mystery !

I have an 8mb ADSL connection but, as I live 1.5 miles from the exchange, have never been able to get a downstream speed higher than 5000 Kbps. My average speed is usually 4200 Kbps. At the beginning of March I rebuilt my computer system and then struggled to get a downstream better than 3200 Kbps. After installing new drivers for the Intel onboard LAN and some other tweaks I managed to get downstream back up to
4500 Kbps at the end of March.

However, since about 4th April, I have been unable to get a downstream better than 2800 Kbps irrespective of the time of day. Nothing has changed within my computer system hardware or software since the end of March when (for almost a week) I regularly had a downstream of 4500 Kbps.

Any helpful advice would be appreciated.

Thankyou

(ISP : Newnet)

You need to find out which part of the chain is slowing you down. A good place to start would be to run the BT speed test to discover your profile. The profile is the speed at which BT pumps data down to you.

http://www.speedtester.bt.com/

It would also be useful to know your modem sync rates and your lines attenuation and SNR margin.

Thankyou for the post John2007.

I have run a BT Speedtest and received the following results :

IP Profile for line 3000Kbps
DSL Connection Rate Upstream 448 Kbps
DSL Connection Rate Downstream 4192 Kbps
Actual IP Through Put 2666 Kbps

I have not run the BT Speedtest since before Christmas and my IP Profile was definitely previously 5000Kbps.

Why and how did this change and what should I do ?

Thanks again for the post.

According to

http://www.dslzoneuk.net/adslmax_explained.php

you will have a profile of 3000 if you have sync'd between 3424 - 3999.

If you maintain your current sync rate for 3 days you should be on a profile of 3500.

To be sync'ing at lower rates than previously something must have happened to affect the line between your modem and the exchange. This could be internal or external.

If it is internal it is your job to sort it out. So you would need to check that filters are properly fitted etc. Look here

http://www.dslzoneuk.net/socket.php

If it is external BT will only do something if your line is sync'ing at 30% less than set during your training period. You will need to ask your ISP to find out what that value was. They will also require you to have run the BT speedtest 3 or 4 times before they look into it.

Thankyou very much john2007.

Excellent information. Looks like I have some work to do !

Thanks again.

I forgot to ask.

Can I do anything to modify/control the sync rate between my modem and the exchange ?

FYI : I have a US Robotics MaxG wireless router/modem.

Thanks again.

Sometimes you can. If you have extension wiring (even if the modem is not connected to an extension) it can act as an aerial for noise, which is always worse at night. If you have extensions, the best thing you can do is to fit a filtered faceplate (assuming you have the new style BT phone socket), and connect the ADSL modem directly to that. Any noise picked up by the extension wiring will be filtered out by the faceplate filter.