Why Wi-Fi speeds are always slower than cable—and how to minimize the gap

You've signed up for a new 500 Mbps plan, but your Wi-Fi speed barely reaches 200 Mbps, while your cable connection hits 480 Mbps. This isn't a provider error or a router defect. The speed difference between wireless and wired connections is a natural phenomenon caused by the physics of data transfer, protocols, and hardware limitations. In this article, we'll look into it. 7 Key ReasonsWe'll explain why Wi-Fi is losing to Ethernet, and show you how to reduce the gap from 50% to 10-15% without buying new equipment.

There's no point in arguing with the laws of physics: radio waves will always be inferior to electrical signals in terms of stability and throughput. But that doesn't mean you have to accept 300 Mbps losses. Proper router settings, channel selection, firmware updates, and even device placement in the room can restore your connection speed. 70-80% of cable speed — and this is already enough for comfortable 4K streaming, online gaming, and working with cloud services.

1. Physical limitations of radio waves vs. electrical signals

The main reason for the difference lies in the method of data transmission. Ethernet uses twisted pair (category 5e/6/6a cable), where the signal is transmitted through copper wires with minimal interference. While Wi-Fi relies on radio waves of the range 2.4 GHz And 5 GHz, which:

• 📡 They dissipate in space (the further from the router, the weaker the signal).
• 🔄 Reflected from walls, furniture and household appliances, creating echoes and interference.
• 📶 They compete with other devices (microwaves, Bluetooth headsets, neighboring networks).

Even in ideal conditions (router and device in the same room, no interference) maximum theoretical speed of Wi-Fi 6 (802.11ax) on frequency 5 GHz - near 9.6 GbpsBut this total channel capacity, which is shared by all connected devices. In reality, one device will receive no more than 1.2–2.4 Gbps (when using 160 MHz channel And MU-MIMO). For comparison, Gigabit Ethernet consistently delivers 940–960 Mbps in practice.

⚠️ Attention: If your router only supports the standard Wi-Fi 4 (802.11n), maximum speed on 5 GHz will not exceed 450 Mbps — even with a perfect signal. Check the model's specifications in the documentation.

2. Losses in protocols and encryption

Wi-Fi spends some bandwidth on overhead: packet acknowledgement, retransmission of lost data, and encryption. Ethernet doesn't do this—packets are transmitted as is. Let's look at the key speed-suckers:

• 🔒 WPA3/WPA2 encryption: adds 10–20% Overhead costs for processing each packet. The weaker the router's processor, the greater the drop.
• 📦 TCP/IP protocol: Wi-Fi uses CSMA/CA (checking the channel before transmission), while Ethernet works on CSMA/CD (collision detection). The first protocol is less efficient.
• 🔄 Retransmission of packets: If a packet is lost (due to interference), it is resent, which eats up time and bandwidth.

For example, at the rate of the tariff 300 Mbps The actual Wi-Fi throughput will be:

• 300 Mbps × 0.85 (protocol losses) × 0.9 (encryption) ≈ 229 Mbps.

Through the cable you will get the same 300 Mbps minus 2–5% for service data.

3. Interference and air traffic congestion

Range 2.4 GHz — the “dirtiest”: not only routers operate here, but also microwave ovens, cordless phones, and Bluetooth devices. At the frequency 5 GHz There is less interference, but there are some nuances here too:

• 📡 Neighboring networks: in an apartment building there may be 10–20 networks on the same channel. They compete for airtime.
• 🛋️ Obstacles: concrete walls weaken the signal 20–50 dB, and metal structures (such as reinforced concrete) can block it completely.
• 🌳 External factors: even the weather affects stability - rain or snow worsens the signal 5 GHz stronger than on 2.4 GHz.

You can check the airtime load using utilities like Wi-Fi Analyzer (Android) or NetSpot (Windows/macOS) If your channel has more 3–4 networks with a higher signal level -70 dBm, it is worth changing the channel manually.

4. Client device limitations

Wi-Fi speed depends not only on the router, but also on receiver on your smartphone, laptop, or TV. For example:

• 📱 Smartphones: even flagship models (for example, iPhone 15 or Samsung Galaxy S23) rarely support channel width 160 MHz on 5 GHzUsually the limitation is - 80 MHz.
• 💻 Laptops: Many budget models are equipped with adapters Wi-Fi 5 at maximum speed 867 Mbps (under ideal conditions).
• 📺 TVs and set-top boxes: Smart TV on Android TV or webOS often use outdated chips Wi-Fi 4.

You can check the capabilities of your device in the specifications on the manufacturer's website or using the command (for Windows):

netsh wlan show interfaces

Search for lines Radio type And Maximum speed.

⚠️ Attention: If your laptop is connected to the router using the standard 802.11ac, but the speed does not exceed 300 Mbps, check if the adapter's power saving mode is activated. In Windows, disable it in Device Manager → Network Adapters → Properties → Power Management.

5. Suboptimal router settings

Even a modern router will slow down if its settings aren't adapted to your network. Here are the key parameters to check:

Set channel width 80 MHz (or 160 MHz, if supported)|Enable WPA3 instead of WPA2|Disable 2.4 GHz, if you only use 5 GHz|Activate MU-MIMO And Beamforming|Update firmware to the latest version-->

Let's take a closer look:

• 📶 Channel width: on 5 GHz choose 80 MHz (or 160 MHz, if the devices support it). 2.4 GHz width 40 MHz may create interference for neighbors.
• 🔒 Encryption type: WPA3 faster WPA2 due to a more efficient algorithm SAE (at the same time improves security).
• 🔄 Opening hours: if the router supports Wi-Fi 6, turn on the mode 802.11ax (sometimes called AX Mode).
• 📡 Transmission power: in some routers it can be increased to 100% (by default it is often 50–75%).

Example of the path to the settings on routers ASUS:

Admin Panel → Wireless Network → Advanced → Bandwidth

How do you know if your router supports Wi-Fi 6?

Look at the device's body - there should be a mark there. Wi-Fi 6 or 802.11ax>. If it's not there, check the model's specifications on the manufacturer's website. Routers with support Wi-Fi 6 usually released after 2019.

6. Problems with equipment and cables

Sometimes it's not Wi-Fi that's to blame, but faulty equipment or incorrect connection:

• 🔌 Cable from the provider: if it is damaged or does not meet the standard (need Cat 5e or higher for speeds >100 Mbps), the speed will be limited at the input.
• 🖥️ WAN/LAN port: There may be a port on your router or computer 100 Mbps instead of 1 Gbps. Check the LEDs - if only the orange one is lit (and not the green one), the port is operating in the mode 100 Mbps.
• 🔋 Router overheating: If the case is hot, the chipset may throttle (reduce performance), which will affect Wi-Fi speed.

You can check the actual port speed through Task Manager (Windows):

1. Open Task Manager → Performance → Ethernet/Wi-Fi.
2. Look at the line Connection speed - if there 100 Mbps, and the tariff is higher, the problem is in the cable or port.

⚠️ Attention: If you use Powerline adapters (Internet transmission via electrical wiring), their maximum speed rarely exceeds 200–300 Mbps In practice, they are not suitable for a gigabit plan.

7. Software limitations and background processes

Even if the network is configured perfectly, speed can be “eaten up” by:

• 🖥️ Background updates: Windows, macOS, Android, and iOS download updates in the background, taking up bandwidth.
• 🎮 Cloud services: Google Drive, Dropbox, Steam sync files even if you don't explicitly run them.
• 🛡️ Antiviruses and VPNs: some programs (for example, Kaspersky or NordVPN) scan traffic, adding delays.

You can check who is consuming your traffic using:

• Windows: Settings → Network & Internet → Data usage.
• Android: Settings → Network & Internet → Data Usage.
• Router: look for the section in the admin panel Traffic Monitor or Bandwidth Control.

FAQ: Frequently asked questions about speed differences

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

No, it's impossible to completely eliminate the difference due to the physical limitations of radio waves. However, it is possible to reduce the gap to 10–15% by:

• Uses Wi-Fi 6/6E on frequency 5 GHz with channel width 160 MHz.
• Connecting devices in close proximity to the router (up to 3 meters).
• Disable all interference (microwaves, Bluetooth, neighboring networks).

In practice, even under ideal conditions, Wi-Fi will be slower than Ethernet on 50–100 Mbps.

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

This is due to airwave congestion. During the day, neighboring networks are more active (more users are online), which creates interference. At night, the number of competitors for the channel decreases, and the router can use it more efficiently. The difference can be as much as 30–50%.

Does the number of connected devices affect the speed?

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

• At 5 connected devices, the speed on each may drop 40–60%.
• Routers with MU-MIMO They distribute the load better, but still lose speed.

Solution: Limit the number of active connections or use QoS (traffic prioritization) in the router settings.

Should I buy a Wi-Fi 6E router to improve my speed?

Only if:

• Your tariff is higher 500 Mbps.
• Do you have devices that support Wi-Fi 6E (For example, Samsung Galaxy S22+, iPhone 15 Pro, laptops on Intel AX210).
• You live in an apartment building with a large number of networks (range 6 GHz less busy).

In other cases, the speed increase will be minimal (or unnoticeable).

Can a router's antenna affect speed?

Yes, but not as much as marketing makes it out to be. Antennas do affect coverage area And signal stability, but not on maximum speed. For example:

• External antennas (TP-Link TL-ANT2408CL) can improve the signal on 10–20 dB, but the speed will only increase if the connection was previously unstable.
• If the router already provides a signal level -50 dBm and higher, replacing antennas will not provide any increase.