Why is Wi-Fi slower than cable? 10 reasons and solutions

Have you noticed that your Wi-Fi internet speed is several times slower than your cable connection? This is a common problem faced by users of both budget and premium routers. Even if your provider promises 100 Mbps or 1 Gbps, over a wireless network you only get 20-50% from the stated speed—or even less. What's the cause and how to fix it?

In this article we will look at 10 key factors, which affect Wi-Fi speed—from incorrect router settings to external interference. You'll learn how to check your actual speed, what settings to change in the admin panel, and when it's time to upgrade your hardware. We'll also explain why even a new router with Wi-Fi 6 It may slow down if you don't take into account a few nuances.

Spoiler: in 80% of cases, the problem can be solved without buying a new device—just properly configure the current one. Let's start with the most obvious, yet often overlooked, issue.

1. Does your provider limit your Wi-Fi speed?

The first thing to rule out is restrictions from the Internet providerMany users mistakenly believe that if a cable connection offers high speed, then Wi-Fi should perform similarly. In fact, your provider may:

• 📉 Throttle traffic for wireless connections (especially on tariffs with "unlimited" Internet).
• 🔌 Limit the speed on the router port, if it is rented from a provider.
• 📡 Block protocols, which are actively used via Wi-Fi (for example, BitTorrent or VPN).

How to check? Connect your computer directly to your ISP's cable (bypassing the router) and run a speed test. Speedtest.net or Fast.comIf the cable speed matches the plan's specifications, but the Wi-Fi speed is significantly lower, the problem lies with the router or network settings. If the cable speed is also lower, call your provider's support team.

⚠️ Attention: Some providers (eg Rostelecom or MTS) the contract specifies the speed"to 100 Mbps, which means the maximum possible speed, but not guaranteed. During peak hours (evenings), speed may drop by 30-50%.

If the provider is not at fault, we move on to the router settings.

2. Wrong Wi-Fi standard: 802.11n vs. 802.11ac vs. Wi-Fi 6

Wi-Fi technology has evolved, but many routers still use outdated standards. Here's how they affect speed:

If your router only supports 802.11n (Wi-Fi 4), then even with the tariff 300 Mbps you will never get more 150 Mbps via wireless network. Solution:

• 🔄 Update your router firmware — sometimes manufacturers add support for new standards.
• 🛒 Buy a router with Wi-Fi 5/6, if the current one is outdated (for example, TP-Link Archer AX6000 or ASUS RT-AX88U).
• 📶 Switch to 5 GHz frequency - it is less congested and supports higher speeds.

⚠️ Attention: Even if the router supports Wi-Fi 6, but your smartphone or laptop won't, the speed will be limited by the capabilities of the client device. For example, iPhone 11 works only on Wi-Fi 5, A Samsung Galaxy S22 - By Wi-Fi 6.

3. Congested 2.4 GHz frequency: neighbors and household appliances

Frequency 2.4 GHz — the most common, but also the most problematic. It's overloaded not only by other Wi-Fi networks, but also by household devices:

• 📱 Wi-Fi neighbors - in an apartment building there may be 20-30 networks on one channel.
• 🔌 Microwaves — operate at a frequency of 2.4 GHz and create strong interference.
• 🎮 Wireless mice/keyboards (especially cheap models).
• 🔋 Wireless charging and some LED lamps.

How to check channel load? Use apps like WiFi Analyzer (Android) or NetSpot (Windows/macOS). If your channel (for example, 6 or 11) too many networks - change it in the router settings:

1. Log into your router's admin panel (usually 192.168.0.1 or 192.168.1.1).
2. Go to the section Wireless → Channel (or Wireless Network → Channel).
3. Select the least loaded channel (eg. 1, 6 or 11 for 2.4 GHz).

The best solution is switch to 5 GHz, where there is significantly less interference. However, keep in mind that the coverage range at 5 GHz is smaller, and some older devices (e.g., smart sockets or printers) may not support this frequency.

4. Incorrect router settings: channel width, operating mode, QoS

Even a modern router will slow down if its settings aren't optimized. Key parameters to check:

🔹 Channel Width

The wider the channel, the higher the speed, but the more interference it creates for other devices. Optimal values:

• For 2.4 GHz: 20 MHz (more stable) or 40 MHz (faster, but may lag).
• For 5 GHz: 80 MHz (recommended for Wi-Fi 5/6).

🔹 Operating mode (Wireless Mode)

If it is set in the settings 802.11b/g/n mixed, the router is forced to support outdated devices, which reduces speed for everyone. Optimally:

• For 2.4 GHz: 802.11n only (if you don't have any old gadgets).
• For 5 GHz: 802.11ac only or 802.11ax only (for Wi-Fi 6).

🔹 QoS (Quality of Service)

Function QoS should prioritize traffic (for example, video calls or games), but often does not work correctly and, conversely, slows down speed. Try disabling it in the section Advanced → QoS.

Where can I change these settings? In the router's admin panel, usually in the section Wireless Settings or Advanced. For popular models (TP-Link, ASUS, Keenetic) the path may differ - look for tabs named "Wireless mode" or "Wi-Fi".

Change the channel to 5 GHz (if supported) | Set the channel width to 80 MHz for 5 GHz | Disable legacy mode | Try disabling QoS | Update the router firmware -->

5. Weak signal: distance, walls, and router location

Wi-Fi is radio waves that weaken when passing through obstacles. Even if the router shows "full signal", the actual speed can drop by 2-3 times due to:

• 🧱 Walls and partitions — concrete and metal weaken the signal by 50-70%.
• 🚪 Distances — the speed drops with each meter (especially at 5 GHz).
• 📡 Poor router placement - in the closet, behind the TV or on the floor.

How to improve coverage?

1. Move the router in the center of the apartment, at a height of 1.5-2 meters (for example, on a shelf).
2. Use Mesh systems (For example, TP-Link Deco or Google Nest WiFi), if the area is more than 100 m².
3. Set up a repeater, but remember: it reduces speed by 30-50%.
4. Change the antennas to more powerful ones (for example, with a coefficient 5 dBi instead of 2 dBi).

You can check the signal level in Windows Task Manager (tab "Wi-Fi") or in mobile applications (WiFi SweetSpots for iOS, WiFi Analyzer for Android). Optimal signal level: -60 dBm and above (the closer to 0, the better).

netsh wlan show interfaces

6. Outdated firmware or "corrupt" settings from the provider

A router's firmware is its operating system. An outdated version can:

• 🐌 Limit the speed because of bugs.
• 🔒 Block new standards (For example, Wi-Fi 6).
• 🛡️ Contain vulnerabilities, which exploit viruses (they steal traffic).

How to update firmware?

1. Find out the router model (written on the sticker at the bottom).
2. Download the latest firmware from official website (TP-Link, ASUS, Zyxel and others).
3. Go to the router admin panel and find the section System Tools → Firmware Upgrade.
4. Download the firmware file and wait for the reboot (do not turn off the power!).

⚠️ Attention: Some providers (eg Beeline or MGTS) block the ability to update firmware on their routers. In this case, you will have to reset the device to factory settings (Reset) and configure it yourself.

If the speed has not increased after the update, check if your router is included in the "blacklist" provider. For example, Rostelecom Sometimes it limits speed on uncertified devices. The solution is to call support and clarify.

7. Viruses, background updates, and traffic thieves

If your Wi-Fi speed has suddenly dropped, it may be due tosteals"another device or program. Common causes:

• 🦠 Viruses on a computer or smartphone (for example, botnets for mining or DDoS attacks).
• 🔄 Background updates Windows, macOS or Android.
• 📥 Torrents or cloud synchronization (Dropbox, Google Drive).
• 👤 Neighbors connected to your Wi-Fi (if the password is weak).

How to find the "culprit"?

1. Open the router admin panel and find the section DHCP Clients List or Connected devices.
2. Check if all the devices are familiar to you. If there are any unknown ones, change your Wi-Fi password.
3. Use traffic monitoring programs: GlassWire (Windows), nethogs (Linux) or Fing (mobile).

If you find a suspicious device, immediately:

1. Change your Wi-Fi password to a complex one (for example, W7f#9Kp2$Lm1!).
2. Enable MAC address filtering (in the section Wireless → MAC Filter).
3. Check your computers with antivirus software (Kaspersky, Dr.Web or Malwarebytes).

8. Hardware limitations: router processor and number of connections

Cheap routers (for example, TP-Link TL-WR840N or D-Link DIR-300) have a weak processor and little RAM. 10+ connected devices they start "brake", because they cannot cope with the load.

How to check?

• Log into your router's admin panel and see the number of connected devices.
• If there are more than 15-20 of them, the router is overloaded.
• Check the CPU load (some firmwares have a section System Status).

Solutions:

• 🔄 Disable unnecessary devices (old smartphones, smart bulbs).
• 🛒 Buy a router with a powerful processor (For example, ASUS RT-AX86U with dual-core 1.8 GHz).
• 🔗 Divide the networks: one for basic devices (5 GHz), the other for IoT gadgets (2.4 GHz).

If you don't have the budget for a new router, you can try alternative firmware like DD-WRT or OpenWRTThey optimize the hardware's performance, but require technical skills for installation.

FAQ: Frequently asked questions about slow Wi-Fi speeds