What is the difference between LAN cable categories, Cat5e to Cat8?

You installed a 10GbE-compatible router, but the speed doesn't seem right. When that happens, what is often overlooked is the "category" of the LAN cable itself.

For those who honestly don't understand what "Cat6" or "Cat6A" means, I will organize the differences between the categories here.

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What is a "category" in the first place?

A LAN cable category is a standard that indicates how much communication performance that cable has. The higher the number, the more it supports higher-speed and larger-capacity communication.

Even if you install a high-performance router, if the cable's performance cannot keep up, you will not be able to achieve the intended speed.

Differences in communication speed and supported frequency by category

Cat5e (100MHz/1Gbps)

A standard established in 1999, it is still in active use for home purposes. For standard internet lines, this is often sufficient performance.

Cat6 (250MHz/1Gbps)

The maximum speed is the same 1Gbps as Cat5e, but the supported frequency is wider, and resistance to noise is improved. It is chosen when more stable communication is desired.

Cat6A (500MHz/10Gbps)

This is a standard that officially supports 10Gbase-T (10 Gigabit Ethernet). If you have installed or are considering installing a 10GbE router, this Cat6A or higher is effectively the minimum line.

Cat7/Cat7A (600MHz to 1000MHz)

While the transmission speed itself is 10Gbps, the shield structure is further reinforced, and it is designed to easily maintain stable communication quality even in environments with a lot of noise.

Cat8 (2000MHz / 40Gbps)

It supports an overwhelming speed of up to 40Gbps, but the reach is limited to within 30 meters. It is a standard intended for short-distance, ultra-high-speed communication, such as between servers in a data center.

In the end, which category should you choose?

General home and office use

If communication of around 1Gbps is sufficient, Cat5e or Cat6 is fine. Many of the cables already in your home fall into this range.

You have installed or are considering a 10GbE router/NAS

Choosing Cat6A or higher is the practical minimum requirement. Even if you go to the trouble of gathering 10GbE-compatible equipment, you cannot achieve the performance if the cables remain Cat5e or Cat6. If you are using 10GbE-compatible equipment like the [RTX1300, why I'm glad I bought it] or the [Yamaha NWR100 review] reviewed in this magazine, please consider reviewing your cables as a set.

Environments with high noise or where long-distance wiring is required

In places susceptible to electromagnetic noise, such as factory or office wiring environments, Cat7 is a candidate.

When ultra-high-speed, short-distance communication equivalent to a data center is required

Cat8 tends to be over-spec for home use. Unless you have a very specific use case, there is no need to force yourself to choose it.

If you are unsure, choosing Cat6A is a realistic compromise that can handle both current 10GbE environments and future expansion.

How to check the category of your home cables

For those who say, "I don't know what category the cables in my house are," here is how to check.

Look at the printing on the cable itself

The standard, such as "CAT6" or "CAT6A," is printed on the cable sheath (the outer skin) every few meters. It is easier to find if you twist the cable slightly to check the side.

Check the packaging or manual from when you purchased it

If you still have the packaging, the standard is clearly stated there.

If the printing has faded and is unreadable

Cables used for a long time may have faded printing that makes them unreadable. In such cases, rather than trying to force an identification, it is one option to go ahead and replace them with new Cat6A or higher cables. Since the cables themselves are not that expensive, it is reasonable to think of this as an investment to eliminate bottlenecks in your overall communication environment.

Pay attention to the categories of in-wall wiring and modular jacks

If you have LAN wiring running inside the walls of your home or office, you need to check not only the cable itself but also the category of the in-wall wiring and modular jacks. If there is even one place with a lower category, that will become a bottleneck.

Frequently Asked Questions (FAQ)

Q1. Can I get 10Gbps with a Cat6 cable?
A. While Cat6 can theoretically support 10Gbps, the conditions are strict, such as the transmission distance being limited to a short range (about 55m or less), so Cat6A or higher is recommended if you want stable 10GbE communication.

Q2. Where can I check the cable category?
A. The cable itself is often printed with labels like "CAT6" or "CAT6A," and the standard is also clearly stated on the package.

Q3. Is there any point in using Cat8 at home?
A. In most general home use cases, you will not be able to fully utilize the performance of Cat8. Unless you are in a special environment where you frequently transfer large amounts of data, Cat6A to Cat7 is sufficient.

Q4. Is it okay to keep using old Cat5e cables?
A. You can use them without any problems for communication speeds around 1Gbps. However, if you are considering migrating to a 10GbE environment, it is worth considering replacing them at this opportunity.

Q5. Is it okay to mix cables of different categories?
A. Communication speed will be limited to the performance of the lowest-rated cable or device. If you are aiming for 10GbE, all cables and devices along the path must support Cat6A or higher.

Summary | Remember that "the bottleneck might be the cable"

The LAN cable category is a simple indicator where a larger number means higher speed and higher performance. For general households, Cat5e or Cat6 is sufficient, but if you have introduced a 10GbE-compatible router or NAS, upgrading to Cat6A or higher becomes a practical necessity.

Even if you have high-performance equipment, it is meaningless if the cable is the bottleneck. If you are dissatisfied with your communication speed, please check not only the router itself but also the category of your cables.

It is not exactly a major investment, but since it is the foundation of your communication environment, I recommend comparing options rather than making an immediate decision. First, by saving them in your Amazon cart, you can carefully compare categories and lengths.

▼ First, save to your cart and compare carefully

For 10GbE-compatible equipment, please also see the Yamaha NWR100 Review as well.