Broadband providers tend to be somewhat shy in disclosing this particular factor but contention ratios can have a huge impact on how close your real world speed of your broadband connection is to the advertised rate.
First of all, broadband providers always – unless otherwise agreed –have multiple users share their infrastructure at the same time. This is on the basis that not every single customer will use their broadband connection at the same time.
So if a broadband provider has 1,000 clients it does not build infrastructure to accommodate 1,000 users. Instead it plans for infrastructure requirements based on a ratio, called the contention ratio.
In this way a broadband provider may build infrastructure for one constant user for every twenty users, a ratio of 20:1. This means that the full performance of their network will be maintained as long as no more than 50 people out of 1,000 use the full capacity of their broadband connection at exactly the same time.
However in peak times more than 50 out of 1,000 users may be using their broadband which means that a contention ration of 20:1 could cause slowdowns in the service. If the contention ratio is 50:1 this can become a problem and could be a major contributor to a user not reaching the advertised broadband speeds.
Of course the lower the contention ratio the higher the cost of the connection as the broadband provider needs to set up and purchase more and more equipment. Businesses are often willing to pay multiples of what a consumer would to get a contention ration of 10:1. For businesses where internet access is absolutely crucial a 1:1 contention ratio may be worth the astronomical price.
Home users however would not benefit from a 1:1 or even a 10:1 ratio but might see the difference between 20:1 and 50:1 in peak times. Unfortunately it is hard to know what the contention ratio of a home broadband provider is; broadband comparison websites don’t include this information.
It is probably worthwhile for a home user who is serious about their broadband to phone various providers to find out who offers the best contention ratio, though this will probably be reflected in the price.