Cat5 and Cat6 Ethernet cables are both popular options for wired networking, but there are some important differences between them and reasons why you're probably better off picking the newer Cat6 standard for your next network upgrade.

Overall Findings

• Supports 100 Mbps Ethernet at up to 100 meters.

• Commonly used in existing networks.

• Cheaper.

• Rarely sold with shielding.
  

• Built to lower manufacturer specifications.
  

• Cables without shielding can be thinner and more flexible.

• Supports 1,000 Mbps Ethernet at up to 100 meters.

• Supports 10,000 Mbps at up to 55 m.

• Backwards compatible with Cat5.

• More expensive.

• More shielding options.

• Stricter manufacturing specifications.

• Thicker cables can be harder to route.

Cat5 and Cat6 Ethernet cables aren't entirely distinct from each other. They both utilize the RJ45 header to connect to devices and networking hardware and are built using twisted copper pairs.

They both transfer data at high speed across networks at low latency. They're available with a range of shielding options and different specifications, such as being rated for use behind walls or with additional fire protection.

However, the raw capabilities of Cat5 and Cat6 cables are quite distinct. Cat6 cables can transfer a lot more data much more quickly than Cat5, and since they're built to a higher specification, they're usually higher quality, with less chance for interference.

They gave broader options for shielding, too, though the thicker cables in those cases can make them a little harder to route through narrower gaps or in larger quantities.

Performance: Cat6 Is Faster and Better Made

• Up to 100 Mbps up to 100 m.

• Maximum speeds supported by a wider range of networking hardware.

• Considerably slower than most Wi-Fi standards.

• Can't support internet speeds faster than 100 Mb.

• Supports 10,000 Mbps at up to 55 m.

• Supports 1,000 Mbps at up to 100 m.

• Requires faster networking hardware to take advantage of greater performance.

• Supports even the fastest internet connections.

When it comes to raw performance, there's no real comparison between Cat5 and Cat6 Ethernet cables.

Cat5 cables are a much older, slower standard, limited to a maximum of 100 Mbps on Ethernet cables up to 100 meters. That speed will cover just about any device with an Ethernet port from the past 20 years, so compatibility isn't a problem. But faster networks are increasingly common today, and 100 Mbps is considerably slower than even older Wi-Fi standards.

Cat6 Ethernet cables support Gigabit Ethernet (1,000 Mbps) for cables up to 100 m long, but if you keep the cable running under 55 m, you can enjoy 10,000 Mbps. You'll need hardware that supports that speed in your router/switch and connected devices to take full advantage, but the option is there for those transferring massive data collections around a local network.

Shielding: Cat6 Has More Options, but It's Thicker

• Typically sold unshielded.

• Lower manufacturer specifications make cables themselves more susceptible to EMI and crosstalk.

• Shielding options are available at additional cost.

• Lack of shielding makes cables lighter, easier to install, and cheaper.

• Options for foil wrapping, metal braids, and splines.
  

• Higher build quality makes cables better protected against EMI.

• Shielding and thicker wire gauge can make cables thicker and harder to route through tight spaces.

Shielding can protect a cable and the data it's transferring from electromagnetic interference and interference from the other wires in the cable (crosstalk).

Cat5 cables are typically sold unshielded, but you can pay extra for shielding in some cases-the options are just more limited than Cat6. That does make Cat5 cables typically cheaper to transport and easier to install since they're more flexible without shielding and have a thicker wire gauge.

Cat6 has a thicker wire gauge as standard, and with shielding like foil wrapping, plastic spline dividers between the twisted pairs, and metal braids, they can offer much greater protection against interference.

This protection is only really relevant in busy apartment buildings, offices, and data centers where there are many other electronic devices and Ethernet cables around. It doesn't really hurt, either, but that additional shielding and wire thickness can make the installation and transport of Cat6 a little more tricky.

Futureproofing: Cat6 Will Eventually Replace Cat5

• Outdated performance.

• Limited shielding options will worsen EMI as more devices come online.

• Much less convenient than Wi-Fi.

• Works with newer Ethernet standards.

• Supports performance well in excess of what most people need.

• Supports a range of shielding options.

• Is backwards compatible with Cat5 and other older Ethernet standards.

If you're building or upgrading a wired network that you want to continue to be performant enough to be useful in the future, there really is no comparison. Cat5 cables are outdated with poor performance and limited shielding options. Most modern devices support faster Wi-Fi speeds, and the limited shielding options make them a poor choice in busy environments.

Cat6 cables offer the kind of performance that data centers and high-end professionals can really use now, but 10,000 Mbps Ethernet is well in advance of what average consumers need. Gigabit Ethernet at longer distances can be saturated by a high-end internet connection, but Cat6 can go far faster than that at more typical cable lengths under 55 m.

Cat6 is also backward compatible with Cat5, so you can just start replacing your cables with Cat6 piecemeal if you prefer. It'll all function just fine, but when you finally replace all networking hardware with faster gear, you'll be able to use the new Cat6 speed to its full effect.

Final Verdict

There are real performance and shielding reasons to choose the newer standard, though if you look at many of the network cables you use today, you may find that many of them are Cat5.

Cat5 and Cat6 Ethernet cables are both fine for transferring data around a wired network, but there is no competition when it comes to choosing one over the other.

Cat5 is old and outdated and has limited shielding options. Cat6 is not only far faster and offers credible competition for today's fastest Wi-Fi standards, but it also has a greater array of shielding options and is built to a higher standard, making it a better overall cable.

These improvements make Cat6 a little more expensive, but its backward compatibility and higher quality make it by far the better choice for your network upgrades.