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Only getting half of my max achievable speeds

Posts: 149
Registered: ‎08-06-2011

Only getting half of my max achievable speeds

I was doing a speed test on page and these were the results. Any idea why my speeds are so much lower than what is achievable?


1. Downstream Test:  -provides background information.

  Download  Speed
  7.76 Mbps
0 Mbps 21 Mbps
Max Achievable Speed


 Download speedachieved during the test was - 7.76 Mbps
 For your connection, the acceptable range of speeds is 4 Mbps-21 Mbps.
 IP Profile for your line is - 11.18 Mbps

2. Upstream Test:  -provides background information.

  Upload Speed
  0.83 Mbps
0 Mbps 0.83 Mbps
Max Achievable Speed


Upload speed achieved during the test was - 0.83Mbps
 Additional Information:
 Upstream Rate IP profile on your line is - 0.83 Mbps


Community Gaffer
Community Gaffer
Posts: 26,599
Thanks: 10,350
Fixes: 1,603
Registered: ‎21-04-2017

Re: Only getting half of my max achievable speeds

Thanks for getting in touch @ashrafmiah93 Looking into this it seems that the BT speedtester may be giving you an inaccurate result, because your router is getting a sync speed of 12.6mbps which is within the expectations of your line at between 5mbps and 11mbps so realistically I'd doubt you'd ever be able to achieve 21mbps.

Having said that, your download speed of 7.76mbps is a tad on the slow side for the sync speed of 12.6mbps. Was that test run on a device connecting to your router wirelessly or using a wired connection?

It may also be worth running a speed test to a third party website such as Here to compare.

Let us know how it goes.

From 31st October 2022, I no longer have a regular presence here as I’ve moved on to a new role.
Anoush Mortazavi
Posts: 1,145
Thanks: 143
Fixes: 6
Registered: ‎30-10-2011

Re: Only getting half of my max achievable speeds

Your downstream IP profile should be 88.2% of your sync speed on ADSL2+, which looks spot on for yours, and your actual download speed should get close to that figure in ideal conditions (few errors, no network congestion etc.)

Can't speak for everyone of course, but the BTW performance test has always shown my maximum achievable speed to be 21Mbps, which appears to be the theoretical maximum for ADSL2+ rather than my actual line capabilities.