What are the differences between Cat 5 and Cat 6 cables?

As the only physical bridge between your router and web-enabled devices, the differences between Cat 5 and Cat 6 cables are worth understanding

Thursday, 16 July, 2020

It’s fair to say the topic of today’s article is not especially sexy.

After all, cables are rarely a leading topic at dinner parties, or something we agonise over in our local electronics store.

You might be wondering whether it’s even worth knowing the difference between Cat 5 and Cat 6 cables. But – perhaps surprisingly – the answer is yes.

It could significantly improve the performance of your home broadband.

Something in the Ether’

Cat 5 and Cat 6 cables are both variants of the Ethernet cable supplied with many computers and broadband routers.

It’s distinguished from a conventional phone lead by the square plug at the end of its chunky (and generally brightly-coloured) cable. This plug is known as an RJ45 connector.

If you ring your ISP to report broadband issues, they’ll probably ask you to connect your wireless router to a desktop or laptop computer using an Ethernet cable.

That’s because a hardwired connection is a faster, more reliable and more secure way of transmitting data from your broadband router than using WiFi.

It rules out many causes of broadband issues, allowing technical support staff to arrow in on your specific problem.

Your router will have at least two Ethernet ports, allowing you to hardwire devices or install Powerline adaptors around the home.

(We recently explained how Powerline adaptors can transform home broadband).

Enhanced offering

Like many supposedly modern phenomena, Ethernet cables have been around for decades.

In 1980, a standard was published establishing Ethernet as a method of distributing data at (for the time) a frankly astonishing 10Mbps.

Gradual improvements culminated in the fifth generation of Ethernet cabling being enhanced in 1999, resulting in a standard known as Category 5 Enhanced, or Cat 5E.

These cables could distribute data up to ten times faster than their non-enhanced predecessors, at 1Gbps.

A few years later, Cat 6 cables debuted. Once again, these were ten times faster than their predecessors.

More significantly for domestic users, whose home broadband speeds lag far behind Ethernet capacity, the newer standard can process more data at any given second.

Think of Cat 5E as a dual-carriageway, and Cat 6 as a four-lane motorway.

Slow-moving data packets in a Cat 5E cable will slow down faster-moving packets.

That’s not ideal if multiple internet activities are taking place at once – which they usually are these days.

There’s also less electromagnetic interference through Cat 6 cables, thanks to relatively low-tech solutions like different ways of twisting the wires inside each plastic tube.

Because cables are relatively affordable to buy, the older standard won’t save you any money. A one-metre Ethernet cable of either generation should cost less than £10.

With little price difference between Cat 5 and Cat 6 cables, it’s easy to see which one represents the better purchase.

Neil Cumins author picture


Neil is our resident tech expert. He's written guides on loads of broadband head-scratchers and is determined to solve all your technology problems!