Each cable category has different capabilities, but the most important is the supported transmission speed. The table below summarizes the differences between the current standards.
| Cable Category | Maximum Length | Transmission Speed |
| CAT 5 | 100 Meters | 0.1 Gbps |
| CAT 5E | 100 Meters | 1 Gbps & 2.5 Gbps |
| CAT 6 | 100 Meters | 1 Gbps & 5 Gbps |
| CAT 6A | 100 Meters | 10 Gbps |
| CAT 7 | 100 Meters | 10 Gbps |
| CAT 8 | 30 Meters | 25/40 Gbps |
CAT 5
We are only mentioning this type for historical purposes; the maximum transmission speed was only 100 Mbps. Outstanding performance in 1995, now not so much.
CAT 5 cable is no longer produced (as far as we are aware), mainly due to its lack of performance and being superseded by the CAT 5E standard.
CAT 5E
Today, this is one of the most widely used standards. CAT 5E cable is capable of performing up to 350 MHz and capable of speeds up to 1 Gbps.
The “e” stands for enhanced; the “enhancement” is due to a better design that significantly reduces crosstalk over the older CAT 5 standard.
As you can see, the answer to one of the most asked questions is YES CAT 5E is capable of 1 Gbps networking!
The IEEE 802.3bz standard allows 2.5 Gbps speed over CAT 5E cabling.
CAT 6
The CAT 6 standard gives higher performance than CAT 5E. Cat 6 can perform up to 550 MHz, and is also designed for 1 Gbps networking. However, CAT 6 can support 10 Gbps speeds over shorter distances.
So, this is where there is a large amount of debate: if both the CAT 5E and CAT 6 standards are designed to support the same speed, then what’s the real difference? As we just mentioned, the CAT 6 standard supports higher frequencies, and this means that it can provide that Gigabit speed more reliably and efficiently.
What does that mean? If you had a 100-meter run of both CAT 5E and CAT 6 in the same environment, the chances are that the CAT 6 cable run would run at 1 Gbps more consistently. It is for this reason that it is recommended to use CAT 6; it is more “future-proof” than using CAT 5E.
The IEEE 802.3bz standard allows up to 5 Gbps speed over CAT 6 cabling.
CAT 6E
There is no such standard, really… It has never been recognized as a standard by the TIA or any other organization, so why are we mentioning it? Some manufacturers advertise and print on their cable jackets “CAT 6E”. As mentioned above, CAT 6 is usually tested to 550 MHz, but some manufacturers test it to 600 MHz. It is up to the manufacturer if they actually advertise and label 600 MHz cable as CAT 6 or CAT 6E; either way, there is no real-world difference between the two.
CAT 6A
This standard is the next evolution of the CAT 6 type described above. The “A” is for augmented (no, there was not a CAT 6E standard). CAT 6A has a significant performance increase over CAT 6, which is designed for 10 Gbps networking.
CAT6A is usually tested and rated at 600MHZ to 750MHz, depending on the manufacturer, and the construction of the cable significantly reduces cross talk of all types.
CAT 6A is still a copper, twisted pair cable using RJ45 connectors, so yes, you can use it in your home network, and the cost of CAT 6A is not that much higher than CAT 6.
CAT 7
CAT 7 has a similar story to CAT 6E, it was never a really a standard, it didn’t receive approval or certification from the IEEE or the EIA. CAT 7 has an S/STP design, meaning each individual wire pair is individually foil-shielded, and there is an overall braid shield between the jacket and shielded wires.
CAT 7 can perform exceptionally well in electrically noisy environments and supports 10 Gbps networking typically. CAT 7 bulk cable is tested to 1000 MHz
CAT 7A
Just like CAT 7, CAT 7A wasn’t an approved standard. CAT 7A (depending on the manufacturer) is tested to 1,200MHz and can support 40 Gbps under certain circumstances. However, the IEEE dictated (after CAT 7A was ratified) that cables officially supporting 40 Gbps required support of up to 2,000 Mhz.
As you can imagine, CAT 7A is not widely available, and as it does not meet the newer requirements for 40 Gbps networking, it is not generally used in data center applications.
CAT 8
CAT 8 is for data center applications, primarily designed to interconnect switches, servers, blade chassis, etc. The standard has two classes:
- Class I (CAT 8.1) – Meant to be used with 8P8C RJ45 connectors
- Class II (CAT 8.2) – Meant to be used with Tera or GG45 connectors
The advantage of using copper over fiber in the cases mentioned above is that copper devices are more energy-efficient than their fiber counterparts. A definite advantage for data center providers seeking power and cooling savings.