Introduction

Unlike Wi-Fi, which is highly susceptible to environmental factors that can impact performance, Ethernet provides a more reliable way to achieve the fastest speeds your connection can deliver, as long as certain requirements are met. This article will help you troubleshoot slow speeds over Ethernet and provide additional information about the benefits of using Ethernet, an overview of Ethernet cable types, and the speeds you can expect on a Fiber connection.

If you're experiencing issues with your wireless connection, please see our Troubleshooting Wi-Fi article.
 

Troubleshooting

Initial Troubleshooting & Diagnostic Questions

The following questions are designed to help identify the potential cause of your issue and determine which troubleshooting category it falls under (e.g., "Getting Exactly 10 Mbps/100 Mbps" or "Other Slow Speed Issues"). If you're unable to resolve the issue using this article and need to contact support, our representatives may ask similar questions to help diagnose the problem. Having this information ready in advance can help our support team troubleshoot more efficiently and speed up the resolution process. 

1. What speeds are you currently seeing? You can run a speed test at https://www.sonic.com/speedtest or, for the most accurate results, download and use the Ookla Speedtest app. Run several tests and record the download speed, upload speed, and latency (ping) for each.
2. How many devices are experiencing the issue?
3. What is each affected device connected to? Is it connected directly to the residential gateway (RG) (i.e., your router), or through a network (Ethernet) switch?

Getting Exactly 10Mbps/100Mbps

If speeds are hovering at or near 10 Mbps (~8.5-9.2 Mbps) or 100 Mbps (~90-95 Mbps), it may be due to outdated or failing hardware. 

• Check the link speed of the device's Ethernet port.
  • The steps for checking the link speed vary depending on the device and operating system (Windows or Mac), and software version. Refer to the documentation for the device or search online for instructions specific to the device and operating system.
  • If the link speed is 100 Mbps, but you have gigabit Fiber service, it may be due to the device’s hardware.
    • You can try changing the link speed in your Ethernet adapter settings. However, if no options above 100 Mbps are available, the hardware may be the limiting factor.
• Check the hardware specifications of the network switch or residential gateway/RG (i.e. Router). 
  • Some third-party equipment may not support full gigabit speeds, or it may not be configured correctly to send and receive data at the appropriate rate.
    • To find your device’s capabilities, refer to the user manual or check the product details online and review the maximum speed for its WAN (input) and LAN (output) ports.
      • If the port is labeled Fast Ethernet (100BASE-T), it supports the maximum speeds of 100 Mbps.
    • If you're unsure how to check your third-party device's settings or specifications, you can temporarily remove it from your setup or bypass it for testing.
  • To test speeds directly to your home connection, connect a computer or other device directly to the Sonic optical network terminal (ONT), also known as the fiber-optic modem. You can view a list of our ONTs here.
    • For the most accurate results, use a device with multi-gig capability and a compatible Ethernet cable.
• Check the Ethernet cable you're using.
  • We recommend using at least a Cat6 Ethernet cable to ensure support for multi-gig speeds.
  • To determine whether the cable is causing the issue, test it with another device or replace it with a known-working cable if available.
  • Over time, Ethernet cables can wear out and lose their ability to deliver fast, reliable performance. Damage such as broken pins or frayed wires can degrade connection quality or cause it to fail entirely.
    • To prevent damage, avoid sharp bends and ensure the cable has some slack. 
• If you're using a USB-to-Ethernet adapter, ensure it is multi-gig capable.
  • These are external devices commonly used with newer laptops that do not include a built-in Ethernet port. They connect via USB-A or USB-C and provide an RJ45 Ethernet port on the other end.
    • Older USB 2.0 Adapters are often limited to 10 or 100 Mbps. Whereas, most USB 3.0 adapters should support speeds of up to 1 Gbps.
• If your device has more than one Ethernet port, try connecting the cable to a different port to see if speeds improve.
  • You can also test a different LAN port on your network switch or residential gateway (RG) to determine whether the original port may be faulty.
• Restart the affected device, network switch, or RG. 

If you’ve completed all troubleshooting steps and the issue persists, please contact our Support Team for further assistance. 
 

Other Slow Speed Issues

If your fiber internet is slower than expected but speeds are not hovering at or near 10 Mbps or 100 Mbps, the issue is likely not related to a link speed limitation. 

• Use the Ookla Speedtest app (instead of the browser-based test) and select the Sonic server closest to your location for the most accurate results.
  • Keep in mind that browser-based speed tests are not always the most accurate way to measure high-speed connections.
    • You can reduce some of their limitations by closing all other tabs and windows except the one running the test, updating your web browser, disabling third-party extensions, or trying a different browser to compare results (e.g. Chrome, Safari, Firefox, or Edge).
• Confirm that your device is connected via Ethernet and not Wi-Fi.
  • Some devices may be connected via an Ethernet cable, but if Wi-Fi is enabled, the device may prioritize the wireless connection instead. In many cases, turning Wi-Fi off will resolve this issue and switch the device to the wired connection.
• When testing on a laptop, make sure it is plugged into a charger and that any power-saving features are disabled.
• Check Task Manager on Windows or Activity Monitor on Mac to see if CPU usage is reaching 100% during the speed test.
  • Close any unnecessary background applications that are using high CPU within Task Manager or Activity Monitor.
  • Alternatively, on Windows, you can reboot into Safe Mode with Networking to limit background programs during the test.
• If a VPN is running in the background, turn it off before testing your speed.
• Check the link speed of your device's Ethernet port.
  • The steps for checking the link speed vary depending on the device and operating system (Windows or Mac), and software version. Refer to the documentation for the device or search online for instructions specific to the device and operating system.
• Check the hardware specifications of the network switch or residential gateway/RG (i.e. Router). 
  • Some third-party equipment may not support full gigabit speeds, or it may not be configured correctly to send and receive data at the appropriate rate.
    • To find your device’s capabilities, refer to the user manual or check the product details online and review the maximum speed for its WAN (input) and LAN (output) ports.
      • Some ports may only support 1 Gbps (1GBASE-T), 2.5 Gbps (2.5GBASE-T), or 5 Gbps (5GBASE-T). 
      • If you're unsure how to check your third-party device's settings or specifications, you can temporarily remove it from your setup or bypass it for testing.
  • To test speeds directly to your home connection, connect a computer or other device directly to the Sonic optical network terminal (ONT), also known as the fiber-optic modem. You can view a list of our ONTs here.
    • For the most accurate results, use a device with multi-gig capability and a compatible Ethernet cable.
• Check the Ethernet cable you're using.
  • We recommend using at least a Cat6 Ethernet cable to ensure support for multi-gig speeds.
  • To determine whether the cable is causing the issue, test it with another device or replace it with a known-working cable if available.
  • Over time, Ethernet cables can wear out and lose their ability to deliver fast, reliable performance. Damage such as broken pins or frayed wires can degrade connection quality or cause it to fail entirely.
    • To prevent damage, avoid sharp bends and ensure the cable has some slack. 
  • Confirm the cable connecting the ONT and the residential gateway (RG) is at least Cat6 and undamaged.
    • You can try replacing the cable to see if the issue improves.
• If you're using a USB-to-Ethernet adapter, ensure it is multi-gig capable.
  • These are external devices commonly used with newer laptops that do not include a built-in Ethernet port. They connect via USB-A or USB-C and provide an RJ45 Ethernet port on the other end.
    • Most USB 3.0 adapters should support speeds of up to 1 Gbps.
• If your device has more than one Ethernet port, try connecting the cable to a different port to see if speeds improve.
  • You can also test a different LAN port on your network switch or residential gateway (RG) to determine whether the original port may be faulty.
• Restart the affected device, network switch, or RG. 

If you’ve completed all troubleshooting steps and the issue persists, please contact our Support Team for further assistance.
 

Contacting Support

If you have any questions or want to speak with someone to further troubleshoot your service, please feel free to reach out to our support team. Support is available between 6am-10pm PT every day and can be reached via phone at 1-888-766-4233 or via a callback request submitted here: https://www.sonic.com/support_cba_request. You can also reach out by email at support@sonic.com or via SMS at (833) 836-0300.
 

Further Reading

An Ethernet connection is generally your best option for fast and consistent speeds. However, hardware and physical limitations can affect the speeds you measure on your connection.

The section below covers the benefits of using a wired connection, the different types of Ethernet cables and their maximum speeds, and the speeds you can expect on Fiber.
 

Wired Benefits

• Capable of delivering consistently faster, symmetrical speeds.
• Ideal for tasks that require stability and low latency, such as video conferences, online gaming, large file transfers & backups.
• Best suited for stationary devices located near the residential gateway (RG) (i.e., router).

Note: Performance can be impacted by several factors including cable type, length, physical damage, external interference, adapter type, and network card.
 

Ethernet Cable Types & Speeds

Ethernet cables come in several different categories with each designed for specific speeds and use cases. Over time, older cable types have been phased out, leaving Cat5e, Cat6, and Cat6a as the most commonly used today.

In general, higher cable categories support faster speeds; however, this often comes at the cost of reduced flexibility and shorter effective distance. See the table below for comparison:

*Speeds shown above represent the maximum achievable speeds for each cable category. Actual speeds may vary depending on your devices, cable condition, network equipment, and other factors.

Most of the time, you can find the cable's rating printed on the cable itself or on a tag attached to it.

Expected Speeds on Sonic 10 Gigabit Fiber

To get the most out of your connection, your router, network equipment, devices, and Ethernet cables all need to support multi-gig speeds. In addition, directly connecting via Ethernet typically provides better performance and is more reliable at achieving the fastest possible speeds compared to Wi-Fi. To learn more, check out the following article: What Speeds Can I Expect on Fiber.