Why vastly different speed tests on different sites?

[stoofa]

I did post this question into another thread - it's possible nobody knew, also possible it was missed, so I'll post here.

I'm wanting to make sure that my line is working as should be and that I'm getting the kind of speeds to be expected. It all feels quick, but like to be sure.
If I run a speed test at http://speedtest.btwholesale.com/ I get, roughly:
75.1mb/17.1mb
I can do a test at http://www.broadband.co.uk/broadband-speed-test/ and get more or less the same, actually a tad faster.
I can run the test 2, 3 times and get the same result, consistently.

If however I pop over to testmy.net for example my results are poor, and consistently so - 11mb/16mb & 10mb/17mb. Upload more or less as expected, download nowhere hear.
If I pop over to speedtest.net I get the same again - download results on somewhere between 9mb & 12mb.
Obviously these are very much below the expected rates on my "up to 80mb" connection.
But the two sites listed at the top are giving much faster results.

Can anyone think why this might be the case? I'm happy to accept the BT Wholesale and the other site are correct, but right now I'm at 2 sites showing good, as expected results and 2 showing very poor results - so still none-the-wiser.

Cheers.

 

[stoofa]

Cheers.
As I've got a couple of sites that definitely seem to be confirming a faster connection I'm not too worried.
I know, from large downloads etc that I'm not on an 8mb connection (as per some of the results).
I'll give it a try over time and see what happens.

Ta

 

[stoofa]

Oh I understand all that - I really do.
If I were getting, for example, a range of results from 55mb - 75mb then I'd accept that as a range, dependant on routing, on traffic etc.
But, when I am constantly getting 71-75 from two sites but I am also constantly getting 8-12 from another that worries me more.
It's a massive difference, not one due to tolerance etc.
It is almost as if some sites do their testing a different way to others and for whatever reason my PC is only responding well to one method.

 

[stoofa]

So because one lesser used indicator is responding poorly you assume you have a problem when the two other well respected sources show you don't? Why not just try downloading some real life content and see if you can max your connection.

I didn't realise speedtest.net was a lesser used indicator? Everyone in the "post your speed" thread was using it.
Now, if you're telling me it's a lesser used one and thus lesser respected one, then I'm happy to ignore the results it is giving me.