Unlimited: the best broadband for downloading?

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THE vast majority of UK ISPs now offer broadband with unlimited data. That's good, because, after all, everything we do online uses data.

But some activities use much more data per second than others, however, and depending on the time of day those activities can become frustratingly slow.

And while unlimited packages offer peace of mind when it comes to how much we're online, be wary of the suggestion that they're good for overcoming that frustration.

Anyone who's tried to watch a video on YouTube only to have it buffer, stutter and pixelate has experienced a lack of bandwidth when it matters.

What we really need is a holy trinity of features: good connection speeds, fair traffic management, and a fair or non-existent fair use policy.

Read on to find why each plays a part in the download experience, or, for those who know the basics, skip ahead to find out what exactly to look for in terms of:

A quick overview

From the least data consumed per second to the most, we'd rank the most common online activities like this:

Services like iPlayer and Netflix often recommend minimum connection speeds, above which we'd expect there to be less of an issue.

But, particularly at peak times, even a decent connection speed might not be enough to prevent the dreaded buffering.

This is where traffic management starts have an effect, with ISPs doing their best to identify what it is we're doing and assign bandwidth accordingly.

If, for example, we're with an ISP that uses traffic management and decide to watch Top Gear on iPlayer during peak hours, the ISP will recognise what we're doing and assign us more or less bandwidth to ease or frustrate our efforts.

The real test of whether our broadband is any good for downloading is when it comes to seriously bandwidth-heavy activities like P2P, gaming, and downloading individual files, whatever their size.

Heavy users or those who live in particular areas face a greater risk of running foul of their provider's fair use policy. The penalties range from having the connection throttled to being disconnected for a while, to being dumped by the ISP.

Putting downloads in the fast lane

1. Speed

If the adverts were anything to go by, we'd be forgiven for thinking that the speed of the connection is all that matters. It certainly doesn't hurt.

Here's a quick guide to how broadband speeds should, in theory, affect downloads.

8Mb 20Mb 50Mb
5MB music track 5 secs 2 secs 1 sec
25MB video clip 26 secs 9 secs 4 secs
4GB film 1 hr 11 mins 24 mins 11 mins

For relatively small downloads there's little performance difference. It's the larger downloads where we'll really feel the benefit of a faster connection.

Once upon a time there were specialist broadband deals for gaming, which also took care of issues about traffic management and fair use. But they've all but disappeared, in large part because the most serious downloaders have migrated to fibre.

And while some providers offering faster connections also manage traffic - like Virgin Media (more here), for example - the boost in speed is such that the experience is still much smoother than it would be elsewhere.

There's more about where to find the fastest broadband in our guide here.

2. Traffic management policies

An ISP's traffic management policy details the amount of bandwidth a broadband provider will allocate to different online activities to keep everything running smoothly, or at least, the priority it will assign to those different activities.

Broadband providers have to manage traffic like this to some extent, otherwise high bandwidth activities would swamp the network and prevent people from ordinary online activity like browsing and checking email.

But it's hard to visualise exactly what this means when it comes to downloading data, so we're grateful to whoever uploaded the following YouTube video.

It shows two downloads taking place side by side, one over a traffic management-free Be broadband (RIP) connection, and one over a traffic managed BT (review) connection.

The unmanaged connection is definitely in the fast lane.

So is traffic management a bad thing? Not entirely.

After all, the ISPs usually design them with the aim of giving as many users as possible a decent online experience - which means balancing the needs of someone downloading the odd email attachment or streaming Eastenders with those of hardcore gamers.

And while we're quite taken with unmanaged connections, some ISPs' traffic management policies explicitly favour download-heavy activities.

While it's not immediately evident to casual browsers, Plusnet (review) have long offered a monthly add-on called Plusnet Pro, which gives the highest possible priority to gaming and VoIP traffic.

Even without that service, their traffic management policy prioritises gaming and VoIP, with streaming and browsing given next highest priority - but other less time sensitive activities like downloading software updates and P2P are slowed a little more.

We'd be willing to bet that's better for downloads than Sky Broadband Unlimited (review), which doesn't have a traffic management policy, but does have a much higher contention ratio.

In Luddite, the contention ratio refers to the balancing act between how much actual bandwidth is available, and how many people are trying to use it. The higher the contention ratio, the lower the amount of bandwidth available to any one user.

Basically, Sky customers, despite their ISP's unlimited data and wide open traffic policy, are more likely to be fighting it out for bandwidth, while Plusnet's customers will find their usage monitored and smoothed where possible.

Eclipse internet - another ISP no longer available to residential customers - had a good reputation for traffic management. They provided a simple tool that allowed their broadband customers to prioritise their own connections.

3. The best (and worst) fair use policies

Finally, those looking for broadband that's good for downloads must take into account their ISP's attitude towards potential bandwidth hogs in the form of their fair use policies.

Like traffic management, fair use policies aim to stop the most data-hungry users from ruining everyone else's online experience by slowing those using the most bandwidth.

More ISPs are moving towards much lighter or even non-existent fair use policies, but some remain less fair than others. See our guide for a full breakdown by provider.

In general, there are two groups of people who should be wary:

The first group need no explanation. But people served by a Market A exchange suffer for being in the least competitive parts of the country.

Not only do providers in these exchanges charge a premium for broadband, they also tend to impose stricter rules on downloads than they do with their "main" packages, even if both are advertised as unlimited.

So people living in more rural areas with less choice of ISP are not only likely to suffer from lower than average connection speeds, but they also face being slowed down further by their provider's fair use policy.

The best advice for everyone, but particularly those in rural areas (more here for those affected), is to check and double check the small print on that unlimited broadband.