ADSL to VDSL - A Consumer Perspective

Sample ADSL to VDSL Upgrade Experiences - Last updated May 2015

TrueNet compares before and after experience of almost 50 volunteer connection upgrades from ADSL to VDSL over the last 2 years.

Research shows that Telecom customers are more likely to experience significant improvements to the speed of their Broadband on conversion from ADSL to VDSL. 

A change to VDSL, from a standard ADSL broadband connection, is most likely to be extremely successful, although for a few it fails to deliver.

Size of ADSL to VDSL improvement:

  • File Download speed = 79%
  • File Upload speed = 672%
  • Webpage download time = 72%

File Download Speed

A change to VDSL generally resulted in dramatic improvements to performance.  Variation in speed was measured, ranging from over 200% increase, to some connections actually going slower.

These results reflect that VDSL operates over a very high frequency, and is more prone to interference than ADSL. Many ISPs advise a wiring upgrade, which may resolve issues.

Charts 1,2 and 3 interpretation:

  • The pink square in each chart is the average performance change.
  • Download speeds on average almost double, but the range is wide.
  • NOTE: All dots above the ADSL=VDSL line are samples with a faster performance after the change to VDSL. The dots below the line are samples that were slower after the change to VDSL.
Chart 1: File Download Speed changes by connection

File Upload Speed

The upload speed is where VDSL really shines, with most connections improving enormously.  No connections actually slowed.  

The average improvement was from 0.8Mb/s to 6.4Mb/s, where users experienced very large improvements in uploading photos, files etc.

Chart 2: File Upload Speed changes by Connection

Webpage Download Performance

Downloading a webpage is a very important activity for most broadband users. TrueNet  found that changes in webpage performance, when upgrading to VDSL, were almost all very positive. The average improvement was from 1.1 seconds, to 0.3 seconds.

NOTE: In Chart 3 the dots below the ADSL=VDSL line show an improvement in performance after the change to VDSL. All dots above the line are samples taking longer after the change to VDSL.

Chart 3: Webpage download time by Connection

Late edit (21 February 2014)

On request from a volunteer TrueNet updated this report to provide a comparison of ADSL downloads before changing over to VDSL. These were compared with the results of VDSL uploads after the change over.  

The decision to upgrade for some people is to achieve an increased upload speed, and while most ADSL is about 1Mb/s, VDSL upload is up to 9Mb/s.  

The volunteer who asked for this chart has a download speed of 8Mb/s, and only three other volunteers changed from ADSL to VDSL with similar download speeds. These showed mixed results.  

However, the slowest ADSL download volunteer still achieved almost 4Mb/s upload speed, a 400% increase. Also worth noting is that most got 7 to 8Mb/s upload speed, independent of ADSL download speed.

Updated section May 2015

This page gets more readers than any other so I like to kepp it up to date.  The following charts provide some simple comparisons of the distribution of speeds we get in New Zealand on copper cables using ADSL or VDSL.  Each column represent the sample size of panelists with that speed, eg for ADSL, 14% of our sample get 13Mb/s during off-peak early morning periods.  Urban and Rural are separated for obvious reason.

Chart 4: Percentage of speeds recorded for Urban ADSL and VDSL panelists

Notice with Rural connections, most get under 10Mb/s, although we do have one VDSL connection in rural with 34Mb/s, they are rare and most likely have the cabinet outside their home.

Chart 5: Percentage of speeds recorded for Rural ADSL (and VDSL) panelists

Just to show the size of the elephant in the room, upload speeds usually increase ten-fold when moving from ADSL to VDSL.  

Chart 6: Percentage of Upload speeds recorded for ALL ADSL and VDSL panelists

All ISPs Now Offer VDSL

VDSL has been offered by only a small number of ISPs until recently; with TrueNet's earliest VDSL connections on Snap, Telecom and Voyager.

Voyager VDSL connections all started as VDSL so we cannot compare before and after.

Telecom the Best for VDSL Upgrades

Download speed improvements by ISP range from a reduction in speed, to 150% increase.  

Telecom customers on conversion to VDSL are more likely to have connections improve speed significantly, although the spread of results is high. We wonder if this is due to a greater focus on wiring upgrades.

ADSL to VDSL speed improvement:

  1. Telecom 54%
  2. Snap 26%
Where is VDSL available? 
Chorus provides most VDSL through a wholesale agreement with ISPs.  Check out their map. Select the "Layers" tab and deselect the ticked UFB and FTTH, then select the "Broadband" tick. VDSL is limited to the very dark brown areas. FInd the Map here.


Details on how we measure are available on our Technical pages
Probe - TrueNet seeks volunteers to support our measurement programme by hosting a "probe' on their home connection. The probe is a simple bridged router that sits beside the modem and conducts a series of tests every hour. Find more details here.
Speed - Throughput, or the peak speed measured during our standard test when downloading an image from our test servers.  
Webpage Download - TrueNet maintains a Standard Testpage (located on our test servers) which is used for measuring the time to download the entire page. 
ISPs - TrueNet has probes measuring almost 20 ISPs but only reports on those where there are 5 or more probes working during any particular month.
ADSL, VDSL, DSL - the standard broadband service provided over a telephone line,  VDSL is a faster version than ADSL. They use similar technology and backhaul, so when appropriate DSL is used when referring to both.
DSLAM - the exchange or cabinet based equipment that your modem is connected to, over the pair of copper wires that are exclusively allocated to your premises.
Ethernet - The wiring used to connect computers to a network, typically an Ethernet cable is coloured blue, with small square connectors at each end.

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