Are Ethernet Cables Slowing Your Connection?
Find out if your Ethernet cables keep you from surfing at brain-melting speeds.
An Ethernet cable may slow your connection if it’s the wrong type or damaged. For example, you shouldn’t use a CAT 5 cable for an internet connection faster than 100 Mbps. And a damaged cable will slow your connection, as will an Ethernet switch box that’s going bad.
To cover all the bases, we’ll explain how you can identify an Ethernet cable’s category, determine if you have the correct one, and troubleshoot possible issues related to Ethernet connections if you already have the right Ethernet cable.
Need a new Ethernet cable?
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First, find your cable’s category
Look closely at your Ethernet cable to find its category number, which will be printed on the outer layer (sheath).
Ethernet Categories tell you information about the speed and reliability of Ethernet cables over certain distances. The higher the category, the newer the design used for the cable, and the faster speeds the cable’s design supports. If your Ethernet cable reads CAT 5 or lower, it’s probably too slow.
Here’s a list of the speeds each category type can deliver:
So, if you have a CAT 5 cable connecting your modem to your router, but you pay for a 400 Mbps internet connection, you’ll never see speeds above 100 Mbps. Your best bet is to use a CAT 5e or CAT 6 cable for connections between 200 and 1,000 Mbps (1 Gbps).
A CAT 6a cable or newer is ideal for multigigabit internet connections.
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If you have the correct cable, continue on to see if there may be problems with the length, the connectors, or other factors.
Check your cable’s length
Most Ethernet cables are designed to perform at a specific sustained speed across 328 feet. For example, a CAT 6 cable has a maximum speed of 1 Gbps, while a CAT 6a cable can hit 10 Gbps—both across 328 feet without any slowdowns. The only exceptions are two CAT 7 cables and CAT 8 cables that support high speeds at shorter distances.
|Category||Max data rate||Range|
|CAT 7||40,000 Mbps (40 Gbps)|
100,000 Mbps (100 Gbps)
|CAT 8.1, 8.2||25,000 Mbps (25 Gbps)|
40,000 Mbps (40 Gbps)
That said, you won’t see any speed changes if you use a short cable versus a long one if they’re both within the specification’s designated range. But all cables that extend beyond their specified range will see signal loss, which results in slower speeds. In other words, you’ll only get a 10 Gbps connection out of a CAT 7 cable if it’s longer than 164 feet in length.
However, some may argue that shorter cables are better than long ones because data takes less time to reach its destination. After all, a car traveling at 50 MPH across 10 miles will reach its destination before a car traveling at the same speed across 100 miles. With Ethernet, the time difference is in nanoseconds, so it’s not worth the argument.
Still, you don’t want to use a 50-foot cable to connect your modem to your router if they’re sitting side-by-side—cable management would be a nightmare.
Check the cable for damage
An Ethernet cable has two or four twisted copper wire pairs wrapped in foil and covered by a sturdy PVC sleeve. If the copper wires are damaged, you will have a slower connection—or no connection at all.
Keep in mind that cats and puppies love to chew on cables, and toddlers may pull on them just because they’re interesting and fun to whip. Try to keep your cables out of reach from teeth, claws, and little fingers.
If you have Ethernet cables located outside, under your home, or in the attic, check them for damage too. They’re just as susceptible to nature and human error as cable TV and telephone lines, so one little nick from a weed eater or a bite from a rodent can slow your internet connection to a crawl.
Check the cable’s connectors
An Ethernet cable has an RJ45 connector on each end. These connectors have eight contacts that touch eight contacts inside the Ethernet port. If they’re dirty, corroded, or damaged, you won’t have a good connection, which causes slower speeds.
Why do some Ethernet cables use gold?
Some Ethernet cables use gold because it’s non-corrosive and more conductive, so keep that in mind when you shop for a new Ethernet cable.
An Ethernet cable’s connector also has a clip that’s used to hold it in place within the Ethernet port. If the clip is broken, the connector will wiggle around in the port, preventing the contacts from making a full connection. You’ll have slower speeds as a result and a possible disconnection if the connector falls out of the port.
Check your PC’s Ethernet port(s)
There are three types of Ethernet ports you can find in today’s electronics: Fast Ethernet, Gigabit Ethernet, and Multigigabit Ethernet.
If you have a desktop or laptop with a Fast Ethernet port, you won’t see speeds above 100 Mbps. Most PCs now ship with Ethernet ports that support 1,000 Mbps (Gigabit Ethernet), and some may even have two Gigabit Ethernet ports you can link together to reach 2,000 Mbps (2 Gbps) speeds when you tether your PC to a compatible device.
If you have an older PC with a Fast Ethernet port, you can work around its limitation by purchasing a USB-to-Ethernet adapter that supports gigabit speeds. The older USB-A 2.0 port supports up to 480 Mbps, which is better than a Fast Ethernet connection. However, you should use a USB-A 3.x or USB-C 3.x port, as they support 5,000 Mbps (5 Gbps) or 10,000 Mbps (10 Gbps), depending on the port’s configuration.
What USB port do you have?
USB ports on PCs typically have two shapes. The “A” rectangular port is older and more common. Those that use the slower USB 2.0 standard are black and have the pitchfork-style symbol printed to the side. Those that use the 3.x standard are blue and have the SS pitchfork symbol printed to the side. The “C” port is smaller and more oval and supports 5 Gbps and higher speeds.
Use a different Ethernet port
If you use Ethernet with a game console, PC, or streaming device, try moving the other end of your Ethernet cable to a different port on the router or gateway. There are usually four at the very least, and the one you’re using may be failing.
A bad Ethernet port will give you slow speeds or no connection at all. By switching ports, you can rule out other possibilities like internet problems, cable issues, and device issues. If your connection suddenly improves by using the new port, then something is wrong with the previous one. Put tape over the troublesome port, so you don’t use it again.
If you have a mesh kit that limits you to just one or two Ethernet ports, you may need to use Wi-Fi instead. Contact the manufacturer if you believe the Ethernet port is having technical issues.
Check your network settings
Log in to your router or gateway’s interface, and make sure you didn’t accidentally block a wired device or limit its connection. The Ethernet cable and port may not be an issue at all, but rather a setting that’s preventing your device from seeing the connection’s full potential.
For example, routers and gateways provide Quality of Service settings that prioritize specific devices and traffic. You may run into speed issues if the router or gateway allocates more bandwidth to a gaming device and prioritizes its associated traffic.
Check your Ethernet switch
If you have multiple Ethernet lines running through your home or office, chances are you may have an Ethernet switch box. They’re ideal if you ignore Wi-Fi altogether and wire everything that accesses the internet. They’re essentially little computers with only one job: forward data.
Like any computing device, switches need to be power cycled from time to time to clear up any hardware and software issues. If disconnecting and reconnecting the power doesn’t resolve your slowdown woes (and you’re sure the switch is the issue), then you may need to replace the unit.
Restart and update your devices
Your Ethernet slowdown may result from a hardware or software issue requiring you to reboot your device.
Be sure that you keep your devices updated, too—install all operating system updates and drivers. An outdated network driver—software that allows the operating system to speak to the hardware—can cause connection problems, like slowdowns and disconnections. Manufacturers generally release new drivers throughout the year to improve performance and stamp out issues, so keeping them current is a must.
Call your internet provider
Cable modems, DSL modems, and fiber optical network terminals (ONT) use Ethernet to deliver internet to a Wi-Fi router. If you replaced the Ethernet cable tethering the two devices and you still have speed issues that aren’t related to your internet connection, there may be problems with the Ethernet port on the modem or ONT. You may also be experiencing a general failure with the modem or ONT itself. Call your provider if you’ve ruled everything else out.
Some homes and offices may have Ethernet problems you just can’t fix. For example, many fiber-to-the-home and fiber-to-the-building services use Ethernet cables draped within the walls and connected to Ethernet jacks mounted in the wall. There may be an issue with the cable or the wall-mounted port that requires a technician to fix.
How do you make Ethernet run faster?
You can make an Ethernet network run faster by getting better hardware and cables.
Most modern PCs, game consoles, streaming boxes, and other devices still use Gigabit Ethernet ports. Modems, routers, and gateways also generally use Gigabit Ethernet ports because most internet connections don’t go beyond 1 Gbps.
The only exceptions are Google Fiber’s 2 Gbps plan, Xfinity’s Gigabit cable internet plan (1.2 Gbps), and Xfinity’s Gigabit Pro fiber internet plan (3 Gbps). Some smaller internet providers like Advanced Stream and Brigham have plans that reach up to 10 Gbps.
But you can increase your home network’s speed by using the latest Ethernet cable—CAT 6a or newer. Plus, many devices with multiple Gigabit Ethernet ports now support link aggregation, which allows you to pair two ports together for a 2 Gbps connection. You’ll also find devices with Ethernet ports supporting 2.5 Gbps, but they’re not as common as Gigabit Ethernet.
Finally, upgrading your Ethernet switch boxes is a good idea (if you use them). The 2.5 Gbps boxes are more expensive and less common than Gigabit Ethernet switches, but you’re investing in the future.
FAQ about Ethernet cables
Who maintains the Ethernet standards?
The Institute of Electrical and Electronics Engineers (IEEE) develops and maintains standards that define how devices share data. You may be familiar with the IEEE 802.11 standard family used for Wi-Fi, like 802.11ac or Wireless AC (now Wi-Fi 5). The 802.3 standard family dictates how Ethernet works in a network, like how fast a cable can send data over a set distance.
Like with Wi-Fi, the IEEE has revised the 802.3 standard over the years to support faster speeds. Each revision adds a letter, like 802.3a and 802.3e. Since these specifications dictate different speeds and how to achieve them, the supporting cables divide into categories.
However, the Telecommunications Industry Association (TIA) maintains the standards specific to Ethernet cables used in non-residential areas and buildings.
Are all Ethernet cables the same?
Not all Ethernet cables are the same. They are currently divided into seven types (or categories) based on their design and supported maximum speed.
What is an Ethernet category?
A category (CAT) refers to how an Ethernet cable supports a specific specification through its design. For example, a CAT 5e cable features four twisted wire pairs capable of supporting a bandwidth of 100 MHz (100 Mbps). A CAT 3 cable has two twisted wire pairs that support a lower 16 MHz (10 Mbps) bandwidth.
The category number represents the revision. Higher numbers represent newer cables, faster speeds, and added shielding that enables those faster speeds. Here’s the complete list:
|Category||Max data rate||Max bandwidth||# of twisted wire pairs||Range||Shielding|
|CAT 3||10 Mbps||16 MHz||2||328 ft.||Unshielded|
|CAT 5||100 Mbps||100 MHz||2||328 ft.||Unshielded|
|CAT 5e||1,000 Mbps||100 MHz||4||328 ft.||Unshielded|
|CAT 6||1,000 Mbps||250 MHz||4||328 ft.||Shielded and Unshielded|
|CAT 6a||10,000 Mbps||500 MHz||4||328 ft.||Shielded|
|CAT 7||10,000 Mbps|
|600 MHz||4||328 ft.|
|CAT 7a||10,000 Mbps||1,000 MHz||4||328 ft.||Shielded|
|CAT 8.1, 8.2||25,000 Mbps|
|2,000 MHz||4||98 ft.|
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Author - Kevin Parrish
Kevin Parrish has more than a decade of experience working as a writer, editor, and product tester. He began writing about computer hardware and soon branched out to other devices and services such as networking equipment, phones and tablets, game consoles, and other internet-connected devices. His work has appeared in Tom’s Hardware, Tom's Guide, Maximum PC, Digital Trends, Android Authority, How-To Geek, Lifewire, and others. At HighSpeedInternet.com, he focuses on internet security.
Editor - Rebecca Lee Armstrong
Rebecca Lee Armstrong has more than six years of experience writing about tech and the internet, with a specialty in hands-on testing. She started writing tech product and service reviews while finishing her BFA in creative writing at the University of Evansville and has found her niche writing about home networking, routers, and internet access at HighSpeedInternet.com. Her work has also been featured on Top Ten Reviews, MacSources, Windows Central, Android Central, Best Company, TechnoFAQ, and iMore.