Cat6a Ethernet Cable vs Cat7 Ethernet Cable vs Cat8.1 Ethernet Cable

Three cables at very different points on the same curve, and reading the bandwidth column top to bottom is the fastest way to buy the wrong one.

Cat 6a is the practical 10 Gigabit cable. It carries that speed across a full 100 metres, it is unshielded and so cheap and flexible, it is a TIA standard, and it terminates in the ordinary RJ45 plug that every switch and computer has. For a house or an office being wired today, it is the default.

Cat 7 has more bandwidth on paper and carries the same 10 Gigabit over the same distance. Its catch is the connector. Cat 7 is an ISO standard defined around GG45 and TERA plugs, which almost nobody fits; a retail cord labelled Cat 7 with RJ45 ends certifies only to the Cat 6a class. It is fully shielded, which helps in electrically noisy installations and adds stiffness everywhere else.

Cat 8.1 is a data-centre cable. It carries 25 and 40 Gigabit - but only across 30 metres, which means its 10 Gigabit reach is a third of Cat 6a's. It is shielded, it is stiff, and it keeps the RJ45 connector, which is why it turns up in retail listings aimed at people who read "40G" and stop there.

The mistake this comparison exists to prevent is buying Cat 8 for a home run longer than 30 metres, or Cat 7 expecting more than Cat 6a from an RJ45 link. For nearly every home and office, Cat 6a is the answer. Cat 7 makes sense in a shielded European installation with the right connectors. Cat 8.1 makes sense between a switch and a server in the same rack, and nowhere else.