Why Wi-Fi speeds are twice as slow as cable: technical reasons and solutions

You've signed up for a new 1 Gbps plan, but your Wi-Fi speed barely reaches 300-400 Mbps, while your cable connection shows 900+? This isn't a provider error or a scam—the speed difference between wireless and wired connections is normal. In this article, we'll look into it. 7 Key ReasonsWhy Wi-Fi is slower than Ethernet, and what to do about it.

Let's be clear: we're not talking about "bad" or "good" internet, but about the physical limitations of technology. Even the most expensive router ASUS RT-AX88U or TP-Link Archer AX11000 will not be able to transmit data over the air as quickly as over a copper cable Cat 6But this doesn't mean you have to put up with lag and slow performance—most issues can be fixed with settings or hardware upgrades.

We analyzed test data from Netgear, Intel and independent laboratories, and also interviewed engineers who deploy networks in offices. It turned out that in 80% of cases, the fault lies not with the providers, but with incorrect router settings, outdated equipment, or external interference. Below is a detailed analysis of each cause with troubleshooting instructions.

1. Physical limitations of Wi-Fi vs. Ethernet standards

The main reason for the difference in speed lies in fundamental differences between wireless and wired data transmission. Even the theoretical maximum for Wi-Fi is always lower than that of Ethernet, not to mention real-world conditions.

For comparison:

• 🔌 Ethernet (cable): standard 1000BASE-T (Gigabit Ethernet) provides stable 940–950 Mbps in real conditions, and 2.5GBASE-T — up to 2.5 Gbps. Interference is minimal, and signal attenuation is virtually nonexistent at distances of up to 100 m.
• 📶 Wi-Fi 6 (802.11ax): theoretical maximum is 9.6 Gbps, but in reality You'll get 600–1200 Mbps (under ideal conditions). However, the speed drops with each meter of distance and obstacle.
• 📡 Wi-Fi 5 (802.11ac): maximum 3.5 Gbps on paper, but real speeds rarely exceed 400–700 Mbps.

Why does this happen? It's because data transfer method:

• 🔄 Ethernet uses full-duplex mode — data is transmitted and received simultaneously over different pairs of wires. There are no waiting times.
• 📶 Wi-Fi works in half-duplex mode — either transmits or receives. Plus, there are delays for packet processing, retransmission of lost data, and interference control.

In addition, Wi-Fi wastes some of the bandwidth on service traffic (control packets, delivery confirmations, encryption). As a result, you get 500–600 Mbps from the stated 1 Gbps, even on a new router.

2. Interference from other devices and networks

If the Ethernet cable is shielded and not exposed to external influences, then the Wi-Fi signal constantly encounters interferenceThere are many sources, from neighbors to household appliances.

The main culprits:

• 📡 Neighboring Wi-Fi networksIn an apartment building, 10–20 routers can operate on the same channel. They interfere with each other, forcing your device to constantly retransmit packets.
• 🔌 Microwaves, cordless phones, baby monitors: operate at a frequency 2.4 GHz and “clogg up” the airwaves with noise.
• 🚗 Bluetooth devices: especially headsets and speakers that use the same frequency 2.4 GHz.
• 🌳 Physical obstaclesWalls, furniture, mirrors, and even aquariums weaken the signal. For example, a concrete wall reduces signal strength by 50–70%.

How do I check the interference level? In Windows, open Command line and enter:

netsh wlan show networks mode=bssid

Look for networks with a strong signal strength (Signal) on your channel. If there are a lot of them, that's the reason for the low speed.

3. Incorrect router settings

Even the most powerful router will slow down if its settings aren't optimized. Most often, problems stem from:

• 🔄 Channel width: if installed 20 MHz instead of 40/80/160 MHz, the speed automatically drops by 2-4 times.
• 🔒 Encryption type: obsolete WEP or TKIP (instead of WPA3-AES) reduces speed by 30–50%.
• 📶 Operating mode: if the router is configured to 802.11b/g instead of 802.11ac/ax, it artificially limits the speed.
• 🔄 Qos (Quality of Service): if enabled but configured incorrectly, it can choke traffic.

How do I check the settings? Go to the router's web interface (usually at 192.168.1.1 or 192.168.0.1) and pay attention to:

1. Chapter Wireless → Channel Width: install 80 MHz For 5 GHz And 20/40 MHz For 2.4 GHz.
2. Chapter Wireless Security: select WPA3-Personal with encryption AES.
3. Chapter Wireless Mode: turn on 802.11ac/ax (if supported).

Set channel width to 80 MHz (5 GHz)|

Enable WPA3-AES|

Disable WPS|

Select the least loaded channel|

Update router firmware-->

⚠️ Attention: If your router is older than 2018, it may not support WPA3 or 160 MHzIn this case, consider upgrading to a model with Wi-Fi 6 (For example, TP-Link Archer AX20 or Xiaomi AX3600).

4. Client device limitations

Wi-Fi speed depends not only on the router, but also on receiver — your laptop, smartphone, or TV set-top box. If the device only supports Wi-Fi 4 (802.11n), even with a router Wi-Fi 6 You won't get more than 150-300 Mbps.

How to find out the capabilities of your device?

To check your current connection speed on Windows:

1. Click Win + R, enter ncpa.cpl.
2. Right-click on the Wi-Fi adapter → State → Speed.

If it is indicated there 72 Mbps or 150 Mbps, your device is operating in mode 802.11n (Wi-Fi 4) and slows down the entire network.

How to update Wi-Fi adapter driver?

1. Open device Manager (Win + X → Device Manager).

2. Find the section Network adapters, right-click on your Wi-Fi module (for example, Intel AX200 or Qualcomm Atheros).

3. Select Update driver → Automatic search.

4. If Windows does not find updates, download the driver from the manufacturer's website (for example, for Intel — [intel.com](https://www.intel.com/content/www/us/en/support.html)).

5. Distance and location of the router

Wi-Fi speed falls exponentially As the distance from the router increases, the loss can reach 70–90% if you're in another room or on a different floor. For comparison:

• 📶 1 meter from the router: 90–100% of maximum speed.
• 🏠 5–10 meters (1–2 rooms): 50–70% speed.
• 🏢 15+ meters (another floor): 10-30% speed or complete shutdown.

The problem is aggravated if the router is:

• 🚪 In a closed closet or behind furniture.
• 🌡️ Near heat sources (radiators, stove).
• 📡 On the floor or in the corner of the room.
• 📦 Near metal objects (refrigerator, microwave).

Optimal router placement:

1. 📍 In the center of the apartment/house.
2. 🔝 At a height of 1.5–2 meters (on a wall or shelf).
3. 🚫 Keep away from household appliances and mirrors.
4. 🔄 Antennas should be directed vertically (if the device is one-story) or at an angle of 45° (for two-story houses).

6. Network congestion and background processes

Wi-Fi is shared resource, and its speed is divided among all connected devices. If the following are simultaneously connected to the router:

• 💻 Laptop (downloads torrents).
• 📱 2 smartphones (streaming YouTube in 4K).
• 🎮 Game console (online game).
• 📺 Smart TV (broadcasts the movie in Ultra HD).

then even with a 1 Gbit/s tariff, everyone will get 100–200 Mbit/s, or even less.

How to check network load?

1. Go to the router's web interface (for example, 192.168.1.1).
2. Find the section DHCP Clients List or Connected Devices.
3. See how many devices are active and how much traffic they consume.

Solutions:

• 🔄 Limit your bandwidth for individual devices in the router settings (section Bandwidth Control or QoS).
• 🕒 Set up a schedule for updates and downloads (for example, at night).
• 📵 Disable unnecessary devices from Wi-Fi (old smartphones, smart bulbs that are constantly “knocking” on the network).
• 🔌 Connect critical devices via cable (for example, a gaming PC or TV set-top box).

⚠️ AttentionSome smart devices (such as CCTV cameras) can consume up to 50 Mbps per stream, even when you're not using them. Check your router settings!

7. Outdated hardware and firmware

If your router was released before 2018, it most likely does not support modern standards. Wi-Fi 6 or 160 MHzAnd outdated firmware may contain errors that artificially limit speed.

Signs that it's time to change your router:

• 🐢 The maximum Wi-Fi speed does not exceed 300 Mbps even near the router.
• 🔄 The router freezes and requires a reboot once a day.
• 📡 No support 5 GHz or Wi-Fi 6.
• 🔌 Ethernet ports only operate at 100 Mbps (Fast Ethernet instead of Gigabit Ethernet).

Minimum router requirements in 2026:

• 📶 Support Wi-Fi 6 (802.11ax) or Wi-Fi 6E.
• 🔌 Ports Gigabit Ethernet (1 Gbit/s).
• 🖥️ Dual-core processor (eg. Broadcom BCM4906 or Qualcomm IPQ8072).
• 📡 Support 160 MHz on frequency 5 GHz.

Recommended models (price/quality ratio):

If you don't plan to buy a new router, at least update the firmware:

1. Log into your router's web interface.
2. Find the section Administration or System Tools → Firmware Upgrade.
3. Download the latest firmware from the manufacturer's website and upload it.

⚠️ Attention: Do not interrupt the firmware update process! If the router is turned off during the update, it may become bricked. Use a backup power supply (UPS).

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

❓ Why is my Wi-Fi speed lower than my cable speed even near my router?

This is normal: Wi-Fi is always slower because half duplex mode, overhead costs for encryption and control packets. For example, with a 1 Gbps data plan, you'll get ~940 Mbps over cable, and 500–700 Mbps over Wi-Fi (under ideal conditions).

❓ Is it possible to get the same speed via Wi-Fi as via cable?

Theoretically yes, but only in laboratory conditions. In practice, even Wi-Fi 6E with channel width 160 MHz will provide no more than 80–90% of the Ethernet speed. For home use, this difference is usually sufficient (for example, 4K streaming only requires ~50 Mbps).

❓ Why is Wi-Fi speed higher at night than during the day?

During the day, neighboring networks are more active, and in the evening, many devices (such as smart TVs) update in the background. At night, there's less interference, so speeds increase. The solution is to switch to a less congested channel. 5 GHz.

❓ Which Wi-Fi channel should I choose for maximum speed?

For 2.4 GHz use channels 1, 6 or 11 (they do not intersect). For 5 GHz select channels with numbers 36–48 or 149–165 (allowed in Russia). Before choosing, check the channel load in the app. Wi-Fi Analyzer.

❓ Will a mesh system help increase Wi-Fi speed?

Mesh system (for example, TP-Link Deco or Google Nest Wi-Fi) solves the problem coverage areas, but it doesn't increase maximum speed. If you already have a good signal but low speed, Mesh won't help. It's needed for larger homes where a single router can't cover all the rooms.