Speed Comparison: VDSL vs ADSL

TrueNet compared the two broadband options available to 90% of New Zealanders to find out how different they are.  The performance of each is compared by speed in both directions over November 2012.

VDSL

We report Upload and Download speeds this month comparing performance with distance, between the DSLAM and the probe, for each of our VDSL probes.  

VDSL results show that for one connection, upload speed is faster than download speed.  This may be due to wireline electrical interference, but is more likely to be due to poor quality home wiring.  

Note that VDSL probe 555 is known to have new ethernet premises wiring, and has the fastest upload performance despite being 900m from the DSLAM.   

Recommendation - get your premises wiring updated before spending on Fibre or VDSL. 

VDSL upload speeds vary between 6Mb/s and 11Mb/s, compare that with ADSL, which has upload speeds between 0.6Mb/s and 1.1Mb/s.  ie VDSL upload speed is 10 times faster than ADSL. 

Note the scales on both sides of the charts when comparing VDSL with ADSL. 

ADSL

To plot the ADSL performance in a way which provides scales suitable for our chart, we have limited the probes in this comparison to Telecom only.  Telecom has more rural customers than other ISPs, so some very long lines are included which provides interesting comparisons as the probes are ordered by distance between DSLAM and probe. ADSL probe performance reduces when the probe is more than 1km from the DSLAM, and reduces more severely beyond 2km.  VDSL is restricted to a limit of about 1km from the DSLAM, but shows no signs of performance reduction over this distance - ie upload speed and download speed appear to be independent of distance.  

VDSL the Preferred Choice in Speed Comparison

VDSL is shown to be very much better than ADSL for both Upload and Download speeds for the same locations.  However, VDSL while able to be supplied by all ISPs, is limited to a few suppliers.   Note: Just two of the five ISPs featured in the TrueNet chart above have significant numbers of probe volunteers.
Our VDSL chart above demonstrates that speeds are independent of distance to the 1km maximum of our probes.  The restriction of a 1km limit for VDSL connections should be reconsidered based on TrueNet results.  Longer cable distances for VDSL are able to provide a far superior performance to that of ADSL. 

Glossary 
Details on how we measure are avalable on our Technical page 

Speed - Throughput or the peak speed achieved during our standard test downloading an image from our test servers 

Webpage Download - TrueNet maintains a Standard Testpage which is used for measuring the time to download the entire page.  This page is visible here, we use a copy located on our test servers for test downloads. 

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 sometimes DSL is used when referring to both. 

Unlimited - A service where there is no monthly limit on the amount of data used.  Specifications for this service include that it may be "Managed" and have "performance reductions applied during peak demand periods". 

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.