Downloads not maxing line speed with FTTC

[#1]

Many thanks for checking Dave, its really great to see plusnet staff monitoring the forum and activly responding.
My only method of testing right now is remotely from work which will obviously impact the results somewhat (i'll test when i'm back home on saturday/sunday) however the one thing i will say is there has been a fair drop in latency.
Speedtest.net used to report around 10ms and its now 5ms so this seems to support your claim about packet loss/re-transmissions.
Equally think broadband latency was 30ms before and now it was 20ms and 15ms with the 2 tests i just ran.
Initial browser 'speedtest' results were actually slightly lower (71.5 Mbps ish, compared with 73Mbps before) but again i'll attribute that to my Teamviewer connection until i've had chance to test locally.
I'll be sure to post my findings after a 'proper' test ASAP.
Thanks again.
George
dick:quote

[#2]

You might be getting more than you think, jolliffegeorge: it depends how you're measuring the "downloads".
Your web browser, for instance, might be reporting the MB/s in terms of the actual disk size of the file ie. 1MB = 1,048,576 Bytes  (that is, on a binary basis of 2²⁰ Bytes).
Your calculation of 73Mbps = 73 million bits per second = 9.1MB/s is based on 1MB = 1,000,000 Bytes  (that is, on a metric basis of 10⁶ Bytes).
The former is usually used for file sizes and is more properly referred to as a mebibyte in SI units (MiB, rather than MB); whilst the latter is generally used for network throughput & bandwidth because, errr... cables are laid in metres and kilometres, and it seemed to make more sense to network people?!... Or something like that.
If you divide 9.1 by 1.049 to convert, you get 8.67MB/s, in terms of actual file size, which is about the download result you most recently got. So factor in some variation and you might be about where you should be, in fact.

[#3]

Thats is a very good theory, and one that hadn't even crossed my mind!
Now what unit does IE10 Use?  - I'm searching furiously.
Equally, by definition is it possible this is how we get the differential between the Plusnet profile and sync speed? and indeed my profile should actually be 78MB/sec?

[#4]

Seems my latency statement was a little premature, it hovers between 10 and 5 on speedtest.net.
Is we assume SuperZoom is right (i think he is) how easy is it to restore my profile to 78Mb/sec and i'll quickly re-test while at work?
All my remote tests are 71Mb/sec on speed test and they were 73Mb/s typically before the profile adjustment (ignoring my remote influence for the moment).

[#5]

Hi there,
Looks like things are set to 73756 on the BT side at the moment, though our profile is at 75800 so a little high - I've not brought it down to 73600 yet (which is what it should be at) but can do if you wish? Can't imagine this will increase the speeds any but just a thought.

[#6]

Well the story so far…
The reason for this thread was to question why my speedtest results (73Mb/sec) do not translate into my actual download speeds (8.6MB/sec), this was soon muted as SuperZoom highlighted that my browser was using the unit of MiB/sec rather than MB/sec thus 100% answering my question.
However…
Since initial profile adjustments were made by Plusnet to try and ‘solve’ my issue I have actually measurably lost performance.
I am now (at best) getting 67 Mb/sec on speedtest.net (and think bband) and my plusnet profile reads at 70.8. (a loss of 6 Mb/sec)
Naturally I cannot obtain my sync rate from the openreach modem (I don’t want to ‘hack’ the ECI box) so I rely on the reading from the PN portal.
I realise my throughput is about right for my profile buy my question is why has my profile dropped by 6 Mb/sec? (It used to be 78 (although should have been about 76)).
Has my sync rate taken a dive recently or is DLM aggressively profiling or something?
Please let me know if this is no longer appropriate for forum discussion and I will raise a ticket.
Any advice appreciated.
Cheers,
George

[#7]

It looks like there's been one or two drops recently, not sure if those were down to you rebooting? Either way I suspect them to be the cause of the drops in profile to be honest.

[#8]

Thanks Matt,
The couple of drops were indeed me, I powered off the modem for about 15 mins on 3 (i think) occasions, note that they weren't just  'reboots'.
What is the FTTC DLM adjustment time? - I'll wait for this to expire before checking again.

[#9]

Quote

What is the FTTC DLM adjustment time?

Hi, assuming you mean how often the profile should update? In that case it would be on the event of a full resynch as with ADSL.
Adam

[#10]

Since my last post I have been monitoring my profile.
I have powered off the OR modem overnight once and my profile won't climb back over 71.
Any ideas why my profile was a 78-76 and now is a 71. It only seemed to fall after an initial profile adjustment via this thread.
Kind regards,
George

[#11]

Adjusting the profile on our side can't have any sort of effect on the BT side of things I'm afraid, that's entirely based (as far as we know) on the error rates shown on your line and the number of disconnections seen by the DLM kit.
I suspect it's more likely to be the crosstalk issues mentioned around here a few times - the more subscribers on a particular cabinet there are, the more crosstalk affects the lines there and the slower the speeds get. Not sure if that's being looked into but I imagine it is.

[#12]

Quote

I suspect it's more likely to be the crosstalk issues mentioned around here a few times

That's exactly what's happened to me over the past 10 months. My D/L has decreased from 43 to 38 as more people have joined the fibre network. Sorry George, you're just going to have to learn to live with it old boy.