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Author Topic: Understanding differences between speed tests  (Read 1993 times)

polymath

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Understanding differences between speed tests
« on: December 18, 2006, 08:32:07 PM »

First post on this forum, I have looked for an answer to my question. If I have missed the answer, just point me to it.

I was recently upgraded to MaxDSL. My connection speed did not improve. My ADSL hardware indicates data consistent with MaxDSL and I do not have disconnection problems (but for some months it does often take some time to make an initial session connection). I am puzzled by differences in speed tests, especially between the two BT speed tests: through speedtest_domain and the 'new' java based performance tool which is accessed through the usual ISP login.

The BT speedtest_domain route gives results consistently around the 2500kbps mark and the best result with the speedtest on my ISP (PlusNet) is a bit slower, around the 2000kbps level (but sometimes down to 400kbps). However the BT java based performance tool gives 'actual IP throughput' rates in the range 3500 - 5900kbps. The latter has no relation to what I can get in practice.

My BT exchange is showing 'red' for virtual paths on the PlusNet exchange status checker.

Do the differences in the 2 BT speedtest tools give any clue to what is causing my 'real world' speed to be still around the 2MB mark? Below are 3 sets of speedtest results from the last few days. I give the BT java based 'Test1' result first and the speedtest_domain and ISP speedtests at times as close as I could manage to each Test1 result. Two of the results are in the off-peak period. I have tried a speedtest_domain test with my firewall and anti-virus off, and it made no difference. These are just example results - I have more! But these 3 illustrate the point.

I have a ticket live with PlusNet on this, but so far the response has not been promising.

Test1 = BT speedtest 217.35.209.142 (java based performance test) though plusdsl.net

15-12-2006 19:28

Test1 comprises of Best Effort Test:  -provides background information.
    IP profile for your line is - 6500 kbps
    DSL connection rate: 448 kbps(UP-STREAM)  8128 kbps(DOWN-STREAM)
    Actual IP throughput achieved during the test was - 5341 kbps

PlusNet speedtest 15-12-2006 19:33:22 1415.2 kbps
BT speedtest@speedtest_domain 217.32.105.42 15-12-2006 19:05 2546 kbps


15-12-2006 09:56

Test1 comprises of Best Effort Test:  -provides background information.
    IP profile for your line is - 6500 kbps
    DSL connection rate: 448 kbps(UP-STREAM)  8128 kbps(DOWN-STREAM)
    Actual IP throughput achieved during the test was - 3703 kbps

PlusNet speedtest 15-12-2006 09:58:32 848.7 kbps
BT speedtest@speedtest_domain 217.32.105.42 15-12-2006 09:46 2594 kbps

14-12-2006 06:38

Test1 comprises of Best Effort Test:  -provides background information.
    IP profile for your line is - 6500 kbps
    DSL connection rate: 448 kbps(UP-STREAM)  8128 kbps(DOWN-STREAM)
    Actual IP throughput achieved during the test was - 5904 kbps

PlusNet speedtest 14-12-2006 06:41:54 2135.7 kbps
BT speedtest@speedtest_domain 217.32.105.42 14-12-2006 06:30 2505 kbps



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kitz

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Re: Understanding differences between speed tests
« Reply #1 on: December 19, 2006, 06:28:02 AM »

Hi and welcome

First ignore the PN speedtester - the file size is very small and it wasnt really designed for the high speeds of Max - even PN will admit its not the best indication as it was originally designed when 512kb speeds were the norm.
One of the speetesters I prefer is the BBMax one which IMHO seems to be pretty accurate.
Theres a list of speedtesters here:- http://www.kitz.co.uk/adsl/speeds.htm

Strictly speaking the BTw speedtest should give you a good indication of whats really going on on your line - because it tests between your home and the BT RAS

The performance tester gives you some additional information that you cant get on other testers - but it traverses your ISP connection so should be an indication of "real world" performance.

Your IP profile is an indication of what your throughput speeds should be under perfect conditions.
Bear in mind this is Maxdsl and welcome to *up to speeds* where more than ever users are seeing bT let contention kick in at the local exchange.  I dont think theres many people on any ISP that sees much over 4Mbish during peak time hours Im afraid.
BT defines acceptable speeds as per here; http://www.kitz.co.uk/adsl/acceptablespeeds.htm

Try running some BBMax speedtests and see what they tell you

Code: [Select]
Perf PN BTw

5341 1415 2546 19:30
3703 848 2594 10:00
5904 2135 2505 06:30
   

Those BTw speedtest do indeed look very weird - what is going on there I really have no idea - its almost as if for something like you say is cutting the speed at around the 2500 mark ??
If the results were the other way round I could perhaps point fingers, but not this way.

BTW with max it is possible to see variations form one min to the next if your exchange is *bursty* type congested...  but what youre seeing isnt that either.

Try running some BBMax (rather than the PN) speedtests and see what they tell you.
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