G.fast is something you may well have not even heard of yet. However, it will be an increasingly big thing in the UK over the next few years. So what is it?
In basic terms, G.fast is a method of using copper phone lines to greatly increase the speed of internet connections using it. Over short distances, it is capable of speeds over 10 times that of current "Superfast" connections in the UK.
BT is currently piloting this technology in a few areas of the country with a view to rolling it out to over 10 million premises by 2020, and to "most of the UK" by 2025. It will likely be branded as "Ultrafast". The current plan is for the top speed available at launch to be 300Mbps. This is about 3 or 4 times as fast as a "Superfast" connection is currently.
It appears that BT are currently favouring this technology over a full "Fibre to the Premises" approach. While this was trialled in some areas for a while, the cost to run fibre all the way to individual premises is very high in some cases due to the logistical difficulty of being able to run the fibre cable through the ancient ducts that currently house the copper that services most of our homes. G.fast is able to squeeze more data down the already existing wires, so is naturally an attractive option in the medium term.
There's bad news for anyone that isn't currently able to access a half-decent internet connection already though. This technology is not going to be able to improve speeds for anyone that doesn't already have access to a "Superfast" connection. It only works well over short runs of copper, so the further you are from the BT cabinet at the roadside, the less effect the new technology will have. It may well be the case that those that are at the fringes of the "Superfast" radius of a cabinet may see very little improvement at all (if any).
So, is it worth upgrading your line to use this new technology when the rollout starts? The answer is "it depends". Today's "superfast" connections are currently more than capable of dealing with a couple of simultaneous 4k video streams from Netflix. Additionally, many consumer routers are not able to process more than 100Mbps (just slightly faster than current 'Superfast' speeds) - even over a wire. However, if you have many people sharing your network and they're all trying to stream stuff at once, you may already be hitting the limits of the current available speeds. And, of course, by 2025, what currently seems like overkill will no doubt be useful in the same way that today's "superfast" speeds will have looked pointlessly fast 10 years ago.