Wi-Fi is slow and the cable is flying: Why is this happening and how to speed up your wireless network?

Have you ever noticed that your Wi-Fi internet speed is noticeably slower than your cable connection? This isn't a coincidence or a glitch on the provider's part—the performance difference between wireless and wired connections is due to the physical limitations of the technology. Even if your plan promises... 1 GbpsYou're unlikely to get more by air. 300–500 Mbps, and in real conditions - even less.

In this article we will look at 7 Key Reasons Why Wi-Fi Is Slower Than CableHow exactly megabits are lost between the router and the device, and what can be done to minimize losses. You'll learn which router settings affect performance and why. 5 GHz not always better 2.4 GHz, and why even the most modern device can choke the entire network's speed. Finally, a self-diagnosis checklist and an FAQ with answers to the most frequently asked questions.

1. Physical limitations of wireless data transmission

The main problem with Wi-Fi is transmission mediumWhile data travels through protected copper wires with minimal interference via cable, a wireless signal travels through open space, encountering numerous obstacles. Here are the main factors that "steal" speed:

• 📶 Signal attenuation: Walls, furniture, and even people absorb some radio frequencies. For example, a concrete wall can weaken the signal 20–50%, and metal structures block it almost completely.
• 🔄 Interference: other routers, microwaves, wireless headphones and even LED lamps operate in the same ranges (2.4 GHz or 5 GHz) and create interference.
• 🌍 Distance to the router: the further the device is from the signal source, the worse the signal-to-noise ratio (SNR) and higher the number of packet retransmissions.
• 🔗 Limitations of the Wi-Fi standard: even Wi-Fi 6 (802.11ax) in real conditions it rarely exceeds 600–800 Mbps, whereas Gigabit Ethernet produces consistently 940–960 Mbps.

For comparison: in ideal laboratory conditions (no interference, 1 meter from the router) Wi-Fi 6 can show up to 1.2 GbpsBut in a real apartment with neighboring networks, walls and household appliances, this figure drops to 2–4 times.

2. Protocols and overhead: why Wi-Fi wastes speed on "maintenance"

Even if the signal is strong, some of the Wi-Fi bandwidth is wasted service data — packet delivery confirmation, connection management, and encryption. In wired networks, these overheads are minimal, but in wireless networks, they can eat up to 30–40% speed.

Let's look at the key differences:

Overhead costs have a particularly strong impact on small data packets (for example, in online games or video chats). For example, when pinging 10 ms via cable and 25 ms Over Wi-Fi, the difference in responsiveness becomes noticeable even to the naked eye.

⚠️ Attention: If you use VPN or Tor, Wi-Fi overhead is compounded by encryption delays, which can double lag. In such cases, a wired connection offers an advantage in 3-5 times.

3. Hardware limitations: router and client device

Wi-Fi speed is limited not only by the transmission medium, but also hardware capabilities router and connected devices. Even if your internet plan is designed for 1 Gbps, the actual speed will be determined by the weakest link in the chain.

Key bottlenecks:

• 📡 Router antennas: model with 2×2 MIMO (two antennas) physically cannot exceed 866 Mbps in the range 5 GHz, even if the standard supports more.
• 🖥️ Device network card: laptop with Wi-Fi 5 (802.11ac) will not get a higher speed 433 Mbps, if an adapter is installed in it 1×1 (one antenna).
• 🔌 WAN/LAN port of the router: if there is a port on the router 100 Mbps, then even with a cable you won’t get more, and with Wi-Fi – even less.
• ⚡ Router processor: cheap models (for example, TP-Link TL-WR840N) cannot cope with processing traffic at high speeds and begin to “slow down”.

You can check the limitations of your equipment in the specifications on the manufacturer's website or using utilities like Wi-Fi Analyzer (Android) or netsh wlan show interfaces (Windows).

Find your router model (on the sticker on the bottom) | Check the Wi-Fi adapter standard of your laptop/smartphone | Measure the speed via cable and compare it with Wi-Fi | Update your router firmware to the latest version -->

4. Router settings that choke speed

Even a powerful router can work on 20–50% slower, if its settings aren't optimized. Here are the most common configuration errors that slow down Wi-Fi:

• 🔄 Channel width: if selected in the router settings 20 MHz instead of 40 MHz or 80 MHz, the throughput drops in 2–4 times.
• 🔒 Encryption type: obsolete WEP or TKIP (within the framework WPA2) reduces speed by 10–15% compared to AES.
• 📡 Transmission power: In some countries (for example, in the Russian Federation), the law limits the power of Wi-Fi to 100 mW, but you can accidentally set a lower value in your router settings.
• 🎯 Operating mode (b/g/n/ac/ax): If the router is configured to be compatible with older devices (eg. 802.11b), it forcibly reduces the speed for all clients.

Optimal settings for maximum speed (if all devices are modern):

Band: 5GHz (or 6GHz if supported)
Channel width: 80 MHz (or 160 MHz for Wi-Fi 6)
Standard: 802.11ac/ax (disable 802.11b/g support)
Encryption: WPA3-AES (or WPA2-AES)
Transmission power: 100% (maximum)

⚠️ Attention: Setting 160 MHz in the range 5 GHz may cause unstable operation if there are many other networks nearby. In apartment buildings, it is better to use 80 MHz.

5. External Interference: How Neighbors and Home Appliances Steal Your Wi-Fi

In urban areas up to 70% of Wi-Fi speed problems are related to external interference. Even if your router is configured perfectly, the signal can be clogged by neighboring networks or household appliances.

The main sources of interference are:

• 📶 Congested channels: in the range 2.4 GHz total 3 non-intersecting channels (1, 6, 11), and if they are occupied by neighbors, the speed drops significantly.
• 🍳 Microwave ovens: operate at a frequency 2.45 GHz, which completely covers Wi-Fi channels in this range.
• 🎧 Wireless devices: Headphones, mice, keyboards, and even baby monitors create background noise.
• 🚗 Electronics in cars: If your router is located next to a window overlooking a parking lot, interference may come from alarms or keyless entry systems.

You can check channel load using the following applications:

- Wi-Fi Analyzer (Android)

- NetSpot (Windows/macOS)

- AirPort Utility (iOS)

6. Features of the operating system and drivers

Sometimes the problem is not in the network, but in software Devices. Outdated drivers, incorrect power-saving settings, or background processes can artificially limit Wi-Fi speed.

What to check first:

• 🖥️ Wi-Fi adapter driver: V Device Manager (Windows) or System information (macOS) Make sure you are using the latest version.
• ⚡ Power saving mode: in the power settings, disable the option Allow the computer to turn off this device to save power.
• 🔄 Background updatesWindows, macOS, and even smartphones can download updates in the background, taking up bandwidth.
• 🛡️ Antivirus/Firewall: some programs (for example, Kaspersky or Avast) scan traffic, adding delays.

On Windows, you can check your Wi-Fi speed using Control Panel → Network Connections, where the current one is displayed connection speed (For example, 433 Mbps). If it is significantly lower than the maximum for your adapter, the problem is most likely in the drivers or settings.

How to update your Wi-Fi driver in Windows

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

2. Find the section Network adapters and select your Wi-Fi module (for example, Intel Wi-Fi 6 AX200).

3. Right-click → Update driver → Automatic search.

4. If Windows does not find updates, download the driver from the manufacturer's website (for example, Intel or Killer Networking).

7. How to check your actual speed and what to do if your Wi-Fi is slow

Before you set anything up, you need to measure speed accurately and understand where exactly packet loss is occurring. Here's a step-by-step diagnostic plan:

1. Cable test: connect your computer directly to the router and check the speed on Speedtest or Fast.comThis will show the maximum speed of your plan.
2. Wi-Fi test near the routerStand a meter away from the router and repeat the test. The difference with the cable will show the wireless transmission loss.
3. Test in different rooms: Check your speed in the places where you usually use the internet. If the speed drops in 2-3 times, the problem is in the coating.
4. Ping test: run ping 8.8.8.8 -t in the command line. If the ping jumps from 10 ms to 100+ ms, there is interference or channel congestion.

If the tests show problems, here's what you can do:

FAQ: Frequently asked questions about the difference between Wi-Fi and cable speeds

Why is the speed on Wi-Fi 100 Mbps, but on cable 900 Mbps, if the tariff is 1 Gbps?

This is a normal situation. Wi-Fi has physical limitations: even Wi-Fi 5 (802.11ac) in real conditions it rarely exceeds 500–600 Mbit/s, and Wi-Fi 4 (802.11n) — and even 150–300 Mbps. Furthermore, the speed depends on the number of antennas in the router and device, interference, and distance. Cable, on the other hand, transmits data almost losslessly.

Is it possible to make Wi-Fi as fast as cable?

It is impossible to completely eliminate the difference, but it can be reduced to 10–20%:

• Use Wi-Fi 6 (802.11ax) with support 160 MHz And MU-MIMO.
• Connect in range 5 GHz (or 6 GHz, if supported).
• Place the router in the center of the apartment, away from interference.
• Disconnect old devices that slow down the network (for example, with 802.11b).

In ideal conditions (router and client with 4×4 MIMO, distance 1 m, no interference) can be achieved 800–900 Mbps, but this will require expensive equipment.

Why does Wi-Fi get faster at night?

This is due to reduced external interference. In the evening and at night, neighbors use their networks less, and microwaves and other noise sources are turned off. As a result, the number of packet retransmissions decreases, and speeds increase. The same thing happens early in the morning.

Does the number of connected devices affect Wi-Fi speed?

Yes, and very significantly. Each device takes up some of the router's bandwidth. For example:

• 1 device: up to 80% of maximum speed.
• 5 devices: 30–50% speed for each (depending on the Wi-Fi standard).
• 10+ devices: speed may drop to 10–20 Mbps to the device if the router does not support MU-MIMO.

Solution: Limit the number of simultaneously connected gadgets or use a router with Wi-Fi 6 and function Band Steering (automatic distribution of devices by ranges).

Which band is better to choose: 2.4 GHz or 5 GHz?

It depends on your situation:

Criterion	2.4 GHz	5 GHz
Maximum speed	up to 150–300 Mbit/s	up to 866–2400 Mbps
Range of action	Passes through walls better	Weaker penetration through obstacles
Interference from neighbors	Strong (few free channels)	Weaker (more channels)
Suitable for	Watching videos, social networks	Games, file downloads, 4K streaming

The best option is to use both ranges simultaneously (if the router supports Dual-Band). Modern devices automatically select the best range.