cancel
Showing results for 
Search instead for 
Did you mean: 

bt speedtest result higher than IP profile?

amcclean
Rising Star
Posts: 1,817
Thanks: 7
Registered: ‎30-07-2007

bt speedtest result higher than IP profile?

Hi,
my bt speedtester result shows a throughput of 5663 with my ip profile listed as 5500. in PN member centre my line rates is 21mb. Is the 21mb figure in PN allowing me to get more than the profile.
podman
5 REPLIES 5
w23
Pro
Posts: 6,347
Thanks: 96
Fixes: 4
Registered: ‎08-01-2008

Re: bt speedtest result higher than IP profile?

I have, occasionally, had a similar result with the throughput exceeding the IP profile, I have also had a few rediculously optimistic results - my record is 126262 kbps with a profile of 5500 kbps and a sync rate of 6652 kbps so it doesn't always report accurately.
I suspect you may be right that a higher PN profile may increase the throughput slightly beyond the BT profile.
Call me 'w23'
At any given moment in the universe many things happen. Coincidence is a matter of how close these events are in space, time and relationship.
Opinions expressed in forum posts are those of the poster, others may have different views.
MJN
Pro
Posts: 1,318
Thanks: 161
Fixes: 5
Registered: ‎26-08-2010

Re: bt speedtest result higher than IP profile?

It is quite common to get spurious results from speed test sites by virtue of what they are intended for and the nature by which they achieve it.
The purpose of a speed test site is typically to ascertain the maximum speed your connection can reach. It is insufficient to simply time how long it takes to download a file of known arbitrary length because that would give the mean average speed and thus would be skewed by temporary issues affecting the throughput. For example, if it took 10s to download a 100Mb file then a crude mean average speed test result would be 10Mbps. However, in actual fact it might have actually downloaded 90Mb in, say, 6s and the last 10Mb took 4s due to momentary congestion somewhere along the path. The result, if taken over the 6s period, would have been 15Mbps and arguably more representative of what your (maximum) speed really is.
It is therefore necessary to ideally determine the maximum throughput achieved at any single instant and hence this can only be done by measuring the throughput per a much shorter time period and repeat this throughout the duration of the test. Attempts to do this for near-instantaneous points in time means that the significance of any errors in timing increases. For example, if we measure how many bits pass in 100 seconds then if we're 1 second out with the timing it's only going to affect the result by a 1%, however if we are measuring over 5 seconds then that same 1 second timing error means an error of 20%, and over 2 seconds we'd be out by 50% and so on and so forth. The error thus increases exponentially and becomes more significant as our time period tends to zero (i.e. as we approach true instantaneous measurements).
Hence, it is not uncommon for spurious results to occur due simply to increasing significance of any timing errors. Ideally such results should be filtered out but whilst this could be achieved by chopping off the top, say, 5th percentile of all results, this itself can end up skewing the results , particularly if the throughput was fairly consistent throughout the test. I suspect these sites simply don't bother themselves with fine tuning like this and instead would likely advise running the tests a few times to help weed out any anomalous calculation errors.
Notwithstanding the above, such a small increase that you saw (~3%) could indeed be simply down to slight inaccuracies in the traffic flow control.
Mathew
amcclean
Rising Star
Posts: 1,817
Thanks: 7
Registered: ‎30-07-2007

Re: bt speedtest result higher than IP profile?

Cheers for the replies guys.
amcclean
Rising Star
Posts: 1,817
Thanks: 7
Registered: ‎30-07-2007

Re: bt speedtest result higher than IP profile?

Check out todays. is there a way pn can release me from the 5500 banding so i can use the rest of the sync speed?
MJN
Pro
Posts: 1,318
Thanks: 161
Fixes: 5
Registered: ‎26-08-2010

Re: bt speedtest result higher than IP profile?

A profile of 5500 is entirely consistent with your sync speed - see [url=http://www.kitz.co.uk/adsl/IPprofile.htm#IP_and_bRAS_profiles]here for further details.
Mathew