Every internet user is familiar with the situation where the plan you paid for with your provider promises 500 Mbps, but your wireless devices barely manage 50-100 Mbps. This isn't always the provider's fault or a hardware malfunction, but often the result of fundamental differences between data transmission technologies.
In a wired connection, information travels along protected copper wires, while radio waves encounter obstacles, airtime competition, and the physical limitations of half-duplex communication. Understanding these processes will help you configure your network correctly.
Physical limitations of the wireless channel
The main reason for the difference lies in the physics of the process. The Ethernet cable provides full-duplex A mode of operation that allows a device to simultaneously receive and send data. In a wireless environment, a device cannot do both at the same time, as the transmitter's own strong signal would drown out the weak incoming signal.
This phenomenon is called half-duplex exchangeImagine a walkie-talkie: to answer, you press a button and stop listening. The router and client constantly switch between "talking" and "listening" modes, which theoretically halves the channel's throughput right from the start.
Furthermore, radio signals are subject to attenuation. While a cable isolates the signal from the external environment, it dissipates over distance in the air. Every obstacle—a wall, a mirror, an aquarium—absorbs some of the signal's energy, forcing the router to reduce speed to maintain a stable connection.
⚠️ Please note: Wall materials have varying absorption rates. Reinforced concrete and metal structures can block up to 90% of the signal, turning fast Wi-Fi 6 into the slow G standard.
The impact of interference and band congestion
The airwaves are oversaturated with signals. In an apartment building, your router "sees" dozens of neighboring networks operating on the same frequencies. This creates a "noisy restaurant" effect: to be heard, the router has to "shout" louder or repeat data packets if they've been distorted by another signal.
The 2.4 GHz band is particularly vulnerable. It's narrow and only accommodates three non-overlapping channels. If your neighbors are using the same channels, problems arise. collisionsDevices are forced to wait for a pause in the air before sending data, which dramatically increases ping and reduces actual speed.
The 5 GHz band is more open, but has less penetration power. However, even here, modern devices such as Bluetooth headsets, wireless mice, and even operating microwave ovens can create short-term but noticeable interference.
Differences between Wi-Fi standards and throughput
Connection speed directly depends on the supported standard. Older devices may limit the entire network. If your router supports Wi-Fi 6 (802.11ax), but the laptop is equipped with a module from 2010 (802.11n), the connection will operate according to the rules of the slowest participant.
It is important to consider not only the generation of the standard, but also the number of antennas. Technology MIMO (Multiple Input Multiple Output) allows for the transmission of multiple data streams simultaneously. If the router has four antennas and the smartphone has only one, multi-stream transmission will not work to its full potential.
Below is a table of theoretical and actual speeds for different standards under ideal conditions:
| Standard | Frequency | Theoretical maximum | Actual speed (near) |
|---|---|---|---|
| 802.11n (Wi-Fi 4) | 2.4 / 5 GHz | up to 600 Mbps | 100-150 Mbps |
| 802.11ac (Wi-Fi 5) | 5 GHz | up to 6.9 Gbps | 400-800 Mbps |
| 802.11ax (Wi-Fi 6) | 2.4 / 5 / 6 GHz | up to 9.6 Gbps | 600-1200+ Mbps |
| Ethernet (Cat5e) | Wire | 1 Gbps | 940-950 Mbps |
Why is the actual speed always lower than stated?
Specifications specify the physical speed of the radio channel. However, a significant portion of the traffic is consumed by packet headers, delivery acknowledgements (ACKs), and encryption overhead. Furthermore, the "airtime" is divided among all connected clients.
Router settings: channel width and encryption
Low speed is often due to suboptimal settings. Channel width is a key parameter. In the 2.4 GHz band, 20 MHz is often the default for stability. Switching to 40 MHz can double the speed, but in an apartment building, this will lead to significant interference and packet loss.
In the 5 GHz range the situation is different. Here channel width 80 MHz or 160 MHz is the standard for high speeds. If you're set to 20 MHz, you're artificially limiting your data flow. Check the settings in the section Wireless Settings or Wi-Fi Master.
The encryption type also matters. Using outdated TKIP instead of AES (CCMP) may limit speeds to 54 Mbps even on modern routers. Always select WPA2-PSK or WPA3 with AES encryption.
Client receiver drivers and power
The problem may lie not with the router, but with the receiving device. Cheap USB adapters often have low antenna sensitivity and heat up, reducing speed. Built-in modules in laptops also vary by class.
Obsolete drivers Network card instability is a common cause of unstable operation. Chip manufacturers (Intel, Realtek, Qualcomm) regularly release updates that improve algorithms for handling interference and power consumption.
Check if power-saving mode is enabled for your Wi-Fi adapter. In Windows, you can find this in Device Manager by unchecking "Allow the computer to turn off this device to save power."
⚠️ Note: Router and operating system settings interfaces are constantly updated. The layout of menu items may differ from that described depending on the firmware or OS version. Please consult the official documentation for your model.
☑️ Wi-Fi Speed Diagnostics
Troubleshooting and Speed-Up Methods
To get maximum speed, first separate your networks. Give the 2.4 GHz and 5 GHz networks different names (SSIDs) and connect high-speed devices (TVs, laptops, consoles) strictly to the 5 GHz band.
Position the router correctly. It should be in the center of the apartment, in an open area, away from radiators and mirrors. It's best to point the antennas vertically upward to ensure horizontal wave propagation.
If the area is large, a single router may not be enough. Use mesh systems that create a single, seamless network, or set up a wired backhaul (connection between nodes via cable), which guarantees wired-like speeds anywhere in the home.
Frequently Asked Questions (FAQ)
Why does my 5GHz Wi-Fi speed drop when I move to another room?
The 5 GHz band has a shorter wavelength, making it more susceptible to obstacles. A single brick wall can reduce the signal by 10-15 dBm, forcing the router to switch to a lower modulation and speed to maintain connection.
Can a torrent downloader slow down internet speeds for other devices?
Yes, active downloading loads not only the bandwidth but also the router's processor. If the buffer is full, new requests (such as opening a page in a browser) may be lost or have a long queue, creating a feeling of lag.
Does the number of connected devices affect the speed of one client?
Absolutely. Wi-Fi works on a queuing principle. The more devices actively transmitting data, the fewer time slots each one gets. Even background app updates on your phone can affect ping in online PC games.