Wildly different speedtester results via FTTC..

[#1]

Hi,
For years now I've been using www.mybroadbandspeed.co.uk which has generally given slightly higher speed results than the http://speedtester.bt.com.
Certainly since coming back from 2 weeks hol mid Jan and during the TM issues I get wildly different results from several testers and wondered if anyone else has the same issue.
All tests done at various times of day/night using same wired connection PC via NetGear WNR2200 and a direct PPPoE connection into the vDSL modem to elimate router problems.
1) The definitive http://speedtester.bt.com gives IP Profile 38363 Down 34-35M Up 1.6M
2) http://www.thinkbroadband.com/speedtest.html always agrees sometimes slightly higher.
3) http://www.speedtest.net gives 'Excelent' ping result but the speed struggles to get to low 20's once I saw 24M Up 1.6.
4) www.mybroadbandspeed.co.uk is now next to useless reporting between 4M to 25M
I was thinking traffic management for different testers, but Wireshark shows they all have the same 'Gold 0x80 Interactive traffic' association.
Doesn't matter what time of day/night and before you ask, yes a different PC produces the same results?
Any thoughts?  I'm having the vDSL modem changed out Monday as that was my first thought but unlike my first overheating one the DSL has never dropped by itself..
Cheers,
Pete

[#2]

If you got 35Mbps from the BT speedtester, but slow speeds *everywhere* else, I would suspect your "Plusnet Profile" speed. What does this page say the "current line speed" is?
BT's speedtester runs without going through the PN traffic management platform, so should be full speed 24x7. I find this to be the case, but that it is less consistent, and perhaps under-reads by a couple of Mbps. Still - getting readings of 34-35 isn't bad.
All the other testers go through the traffic-management platform. Both the "Extra Fibre" and "Value Fibre" packages are restricted to 20Mbps browsing speeds in the eveing 6-11 slot. In practice, I've found that the limit is usually between 22 and 24Mbps. So you'll have to check the times when you've been running those other tests to see if they were within those times.
Outside the managed period, I get the most consistent results from Speedtest.net, provided I am using a wired connection to the router, and use the Newbury server. Other servers work OK, but a little less consistently.
There is an issue at getting absolute top speed - I would either get 35Mbps or 37.5Mbps, depending on circumstances. There are a couple of threads called "Missing Mbps" and Speed artifically low by 2.5Mbps which you might want to read through. Once you get predictable results, then you might want to add your name to the list.

[#3]

Thanks for your reply, but it doesn't seem to matter what time I test it (am/pm), the Thinkbroadband one always agrees with the BT tester give or take a little and I can see the consistent 60 - 70M file downloading on my traffic meter at the good speed.
That's why I thought perhaps the TBB tester was excluded from the TM effect like the BT Tester.
I'm on Extra Fibre ( no Pro Add on) and I saw the threads you mention and asked AW to see if there was anything wrong with my Profile.  The only thing that has happened along with everyone else is the PN Profile indicates 20M from it's original 37M?
While I run the mybroadbandspeed the dial stutters, sometimes doesn't move then gives the result.  I can see this stuttering/stalling effect on the Traffic meter and it looks like the size of file used for the download is tiny compared with the TBB one in the 60 - 70M range.
The speedtest.net suffers the same stalling effect visible on the traffic meter but is always 10M down give or take.
I'll wait till the new vDSL modem is put in on Monday but as far as I can see 1am to 7am on Extra Fibre all protocols should be at line speed, so I'll have to stop up late one night to see what happens as that is the only slot I haven't tried...
I changed gateway this morning and no improvement.
I know when my first vDSL overheated the error rate increased and throughput was effected and eventually the DSL sync flashed until I got the fan out.  It was replaced by the same old version so logic doesn't suggest it, but this all started after we came back and had the heating on a lot as it had been quit mild upto Xmas - we'll eliminate that angle Monday.
Pete

[#4]

I am by no means an expert on Fibre speeds, but I note you stated your "PN Profile indicates 20M". I would say that whilst this is the case you won't get speeds faster that 20M. You need to discover why it's 20M and do whatever for it to go back to it's original 37M?

[#5]

Hi Anotherone,
I would normally agree, but Adam from PN tweaked something as per the Missing Mbits thread and several of us have this FTTC config now but it hasn't affected me ref the varying speedtester results.
I'm having the modem changed out today and just typically BT have changed their tester over the weekend and I keep getting 'Test Error. - go away message!
I am amazed i get the high sync IP profile anyway as I reckon I'm a good 700 - 800 m away from the FTTC cab.
Hopefully I can get one reference BT test before my 1pm to 5pm slot
Pete