Why Wi-Fi internet speed is faster than cable: an analysis of the reasons and solutions

A paradoxical situation: you connect your laptop or PC to your router via cable, expecting maximum speed, but the test shows lower results than over Wi-Fi. It's logical to assume that a wired connection should be more stable and faster—so why does reality contradict this theory? There are several reasons for this behavior, including hardware limitations and network settings.

Many users mistakenly believe that Ethernet cable always outperforms a wireless connection. However, modern Wi-Fi standards (e.g. Wi-Fi 6 or Wi-Fi 6E) are theoretically capable of providing speeds up to 9.6 Gbps, while Gigabit Ethernet is limited 1 GbpsBut it's not just about standards—the nuances of network configuration, equipment quality, and even the physical condition of the cable are important.

In this article we will look at 7 Key ReasonsWe'll explain why Wi-Fi can outperform cable in speed, and we'll also provide practical recommendations on how to restore Ethernet's lead. If you're facing a similar issue, read on to understand where your network's bottleneck is.

1. Limitations of the old Ethernet cable or port

The most common cause is using outdated cables or network equipment. Even if your router supports gigabit speeds, Category 5 cable (Cat5) physically incapable of transmitting data faster 100 Mbps at distances greater than 50 meters. And if the cable is damaged or poorly terminated, the speed drops even further.

Check the markings on the cable:

• 🔹 Cat5 — to 100 Mbps (obsolete, not recommended)
• 🔹 Cat5e — to 1 Gbps (minimum standard for modern networks)
• 🔹 Cat6/6a — to 10 Gbps (optimal for home networks)
• 🔹 Cat7/8 — to 40 Gbps (overkill for most users)

If your cable is over 10 years old, there is a good chance it is Cat5.

The second part of the problem is the network ports on the router, computer, or laptop. For example, many budget router models are equipped with ports Fast Ethernet (100 Mbps), even if the case says "Gigabit." Check the specifications of your device in the documentation or through device Manager (in Windows).

⚠️ Attention: If there is no marking on the cable, and the speed test shows exactly 100 Mbps, most likely you have Cat5 or damaged Cat5eReplacing the cable with Cat6 may solve the problem without any additional settings.

2. Incorrect network adapter settings

Even if the cable and ports support gigabit speeds, network card settings can artificially limit bandwidth. In Windows, this is often due to settings duplex mode or connection speeds, which by default may be set to automatic detection - but this does not always work correctly.

How to check and fix:

1. Open device Manager (Win + X → Device Manager).
2. Expand the section Network adapters and find your Ethernet card (for example, Realtek PCIe GbE Family Controller).
3. Right click → Properties → Advanced.
4. Find the parameters Speed & Duplex or Speed ​​and duplex.
5. Install manually 1.0 Gbps Full Duplex (if your equipment supports gigabit).

Also check if energy saving features are enabled for your network adapter:

• 🔌 In the same adapter properties, go to the tab Power management.
• 🔌 Uncheck the box Allow the computer to turn off this device to save power.

These settings are especially relevant for laptops, where power saving mode may be enabled by default.

3. Overloading the router's Ethernet subsystem

Many routers, especially budget ones, have common Ethernet controller, which distributes bandwidth among all ports. For example, if you have a 4-port router with gigabit ports, this doesn't mean each port can simultaneously deliver 1 Gbps. Often, the combined speed of all ports is limited. 2–3 Gbps.

How does this manifest itself:

• 📉 When connecting multiple devices via cable, the speed on each device drops.
• 📉 If one device is downloading data at maximum speed, the others are slowing down.
• 📉 Wi-Fi can work faster because it uses a separate controller.

Solutions:

• 🔧 Connect devices to different ports (if there are several).
• 🔧 Use a router with dedicated controller for each port (for example, chip-based models Broadcom BCM4908 or Qualcomm IPQ807x).
• 🔧 If your router is old, consider upgrading to a model that supports it. Multi-Gig Ethernet (2.5G/5G/10G).

⚠️ Attention: If your router was manufactured before 2018, there's a good chance its Ethernet subsystem won't be able to handle the simultaneous load of multiple gigabit devices. Check the model's specifications on the official website.

4. The influence of router drivers and firmware

Obsolete network card drivers or router firmware These issues can cause Ethernet lag, while Wi-Fi operates at full speed. Manufacturers regularly release updates that fix bugs and optimize performance.

How to update your network card driver:

1. Find out the adapter model in Device Manager.
2. Download the latest driver from the manufacturer's website (for example, Realtek, Intel, Broadcom).
3. Remove the old driver via Control Panel → Programs and Features.
4. Install the new driver and restart your PC.

Updating the router firmware:

• 🔄 Go to the router's web interface (usually at 192.168.1.1 or 192.168.0.1).
• 🔄 Find the section System Tools → Firmware Update.
• 🔄 Download the latest firmware from the official website and upload it manually.

⚠️ Attention: Don't update the firmware over the air (via the web interface without downloading the file)—this could brick the router if it crashes. Always use manual firmware downloads.

What should I do if my router stops working after updating the firmware?

If your router is not responding after an update, try resetting it to factory settings (button Reset for 10-15 seconds). If this does not help, you will need to reflash the firmware through TFTP mode (look for instructions for your specific model).

5. Problems with MTU and packet fragmentation

MTU (Maximum Transmission Unit) — This is the maximum size of a data packet that can be transmitted without fragmentation. If the MTU value is too high or too low, it leads to packet loss and a drop in speed. Wi-Fi often operates more reliably because it automatically adjusts the MTU to network conditions.

How to check and change MTU for Ethernet:

1. Open Command line (Win + R → cmd).
2. Enter the command:

   ping -f -l 1472 ya.ru

   If packets are not fragmented, reduce the number 1472 by 8 (for example, 1464, 1456) until the ping starts to pass without fragmentation.

3. Optimal MTU value = 1472 + 28 = 1500 (standard for Ethernet). If packets are fragmented during 1472, your actual MTU is lower.

To change MTU in Windows:

• 🔧 Open Network connections (Win + R → ncpa.cpl).
• 🔧 Right-click on the Ethernet connection → Properties → Configure → Advanced.
• 🔧 Find the parameter MTU or Jumbo Frame and set the optimal value (usually 1500).

6. External interference and Wi-Fi signal quality

It would seem, what does Wi-Fi have to do with this if we are talking about a wired connection? The fact is that The router can prioritize wireless traffic., If:

• 📶 Setting up QoS (Quality of Service) gives priority to Wi-Fi.
• 📶 Mode enabled Band Steering (automatic switching between 2.4 GHz and 5 GHz), which reserves some bandwidth for wireless clients.
• 📶 Used MU-MIMO or OFDMA (technologies that optimize Wi-Fi but do not affect Ethernet).

How to check QoS settings:

1. Log into your router's web interface.
2. Find the section QoS, Bandwidth Control or Traffic.
3. Check if Wi-Fi traffic is being prioritized. If so, disable QoS or reset the priority.

It is also worth considering that modern Wi-Fi standards (For example, Wi-Fi 6) use technologies like 1024-QAM And 160 MHz channels, which, under ideal conditions, can exceed the speed of older Ethernet. However, this is only relevant for devices that support these standards (e.g., Samsung Galaxy S22 or iPhone 13 With Wi-Fi 6E).

7. Hardware limitations of the device (laptop, PC, TV)

Sometimes the problem is not in the network, but in network card of your device. For example:

• 💻 Budget laptops often come equipped with Ethernet ports Fast Ethernet (100 Mbps), even if the rest of the network is gigabit.
• 🖥️ Integrated network cards in low-end motherboards may have speed limitations.
• 📺 Smart TV or set-top boxes (for example, Xiaomi Mi Box) often connect via Wi-Fi faster than via cable due to weak Ethernet controllers.

How to diagnose:

1. Connect another device (for example, a PC instead of a laptop) to the same cable.
2. If the speed has increased, the problem is in the network card of the first device.
3. Check the specifications of your model on the manufacturer's website.

Solutions:

• 🔧 Use USB-Ethernet adapter (For example, TP-Link UE300 with 1 Gbps support).
• 🔧 For PC, install PCIe network card (For example, Intel EXPI9301CT).
• 🔧 If the device is old (for example, Smart TV 2015) - consider upgrading.

⚠️ Attention: Some USB-Ethernet adapters (especially cheap chip-based ones) Realtek RTL8153) may not deliver full gigabit speeds due to USB 2.0 limitations. Choose adapters with USB 3.0 and chips ASIX AX88179.

FAQ: Frequently Asked Questions About Wi-Fi vs. Ethernet Speed

Can Wi-Fi 6 be faster than Gigabit Ethernet?

Yes, theoretically Wi-Fi 6 under ideal conditions (close range, no interference, support for 160 MHz channels) it can exceed the speed 1 GbpsHowever, in practice, the stability of Wi-Fi depends on many factors, while Ethernet provides constant speed without fluctuations.

Why does the cable speed fluctuate (sometimes 100 Mbps, sometimes 1 Gbps)?

This is a sign of an unstable connection caused by:

• 🔌 Damaged cable or connectors.
• 🔌 Automatic speed switching due to interference.
• 🔌 A faulty port on the router or device.

Try replacing the cable with Cat6 and check the ports for physical damage.

How do I check if my router supports Multi-Gig Ethernet?

Check the model's specifications on the manufacturer's website. Look for any mention of ports. 2.5G, 5G or 10G. For example:

• 🔹 ASUS RT-AX89X - 2 ports 10G.
• 🔹 TP-Link Archer AX11000 - 1 port 2.5G.

If there are no such ports, your router is limited. 1 Gbps.

Does Ethernet cable length affect speed?

Yes, but only if the cable is of poor quality or exceeds the maximum allowed length:

• 📏 Cat5e/Cat6: to 100 m without losses (for 1 Gbps).
• 📏 Cat6a/Cat7: to 100 m For 10 Gbps.

If the cable is longer or damaged, the speed will drop. For long lines (over 50 m), use Cat6a or optics.

Is it possible to increase Ethernet speed beyond 1 Gbps on an old router?

No, if the router doesn't have ports 2.5G/5G/10G, its hardware limitations will not allow it to be exceeded 1 GbpsThe only way out is to replace the router with a model that supports it. Multi-Gig Ethernet.