Many users wonder why advertised internet speeds don't match actual wireless connection speeds. Often, providers promise 500 Mbps, but on a smartphone or laptop, the numbers are significantly lower. This is because WiFi throughput depends not only on the provider's tariff, but also on the physical limitations of the wireless protocol.
Under ideal laboratory conditions, equipment can deliver the maximum values specified in its specifications. However, in a typical apartment or office, the situation is radically different. The signal is affected by walls, a microwave oven, neighboring routers, and even an aquarium. Therefore, it's important to understand the difference between the standard's theoretical potential and the actual data transfer rate.
A detailed analysis of current communication standards will help you understand the confusing specifications. We'll examine how channel width and the number of antennas affect the final result, and why an older router can throttle speeds even with a premium data plan.
Theoretical maximum vs. actual speed
Equipment manufacturers always list impressive figures on their packaging, such as 1200 Mbps or 3000 Mbps. This is the combined theoretical speed of all bands and antennas of the device under ideal conditions. Actual throughput is usually only 40-60% of the stated value. due to protocol overhead and interference.
The TCP/IP protocol, used for data transmission, adds service headers to each packet. This is necessary for accurate data delivery, but it reduces the channel's payload. Furthermore, the wireless network operates in half-duplex mode: a device cannot simultaneously receive and transmit data on the same frequency, which splits the bandwidth in half.
It's also important to consider the distance to the access point. The further you are from the router, the lower the connection speed due to signal attenuation. Even if your phone is showing full speed in the next room, this doesn't guarantee maximum speed, as the signal quality (SNR) may already be low.
The evolution of WiFi standards and their speed indicators
Wireless technologies are advancing rapidly, with each new standard bringing significant performance gains. Understanding the differences between WiFi generations will help you choose the right equipment for your home or office.
Modern devices most often use the 802.11ac (WiFi 5) and 802.11ax (WiFi 6) standards. They operate primarily in the 5 GHz band, which is less crowded than the older 2.4 GHz band. However, legacy standards are still found in budget devices.
Below is a table showing the theoretical limitations of different wireless generations using a single spatial stream (antenna).
| WiFi standard | Frequency range | Max speed (1 thread) | Year of implementation |
|---|---|---|---|
| 802.11n (WiFi 4) | 2.4 / 5 GHz | 150 Mbps | 2009 |
| 802.11ac (WiFi 5) | 5 GHz | 433 Mbps | 2014 |
| 802.11ax (WiFi 6) | 2.4 / 5 / 6 GHz | 600 Mbps | 2019 |
| 802.11be (WiFi 7) | 2.4 / 5 / 6 GHz | up to 3 Gbit/s | 2026 |
It's worth noting that these figures are for a single antenna. Modern routers use MIMO technology, multiplying the speed by the number of antennas. For example, a router with three antennas on the WiFi 5 standard can theoretically deliver speeds of up to 1300 Mbps.
The influence of channel width on throughput
One of the key parameters directly affecting speed is channel width. Think of a road: the wider it is, the more cars (and data) can travel on it simultaneously. In router settings, this parameter is designated as Channel Width.
In the 2.4 GHz band, the standard channel width is 20 MHz. Increasing the channel width to 40 MHz in this band often leads to severe interference, as the entire band is very narrow and congested with neighboring channels. Therefore, for 2.4 GHz, increasing the channel width rarely improves speed, but it is guaranteed to increase instability.
The situation is completely different in the 5 GHz band. More free space is available here. Using a channel width of 80 MHz or even 160 MHz allows you to achieve the maximum speeds of WiFi 5 and WiFi 6. However, if you live in a densely populated high-rise building, a wide channel may pick up more interference from neighboring networks.
⚠️ Attention: Automatic channel width selection in routers doesn't always work correctly. If you're experiencing speed drops, try manually setting the 5 GHz band to 80 MHz to find a balance between speed and stability.
To configure this setting, you need to log into the router's web interface. Typically, the path looks like this: go to Wireless Mode → WiFi Settings → Basic SettingsHere you can select the desired value from the drop-down list.
MIMO and MU-MIMO Technologies: How Antennas Speed Up WiFi
MIMO (Multiple Input Multiple Output) stands for the use of multiple antennas to simultaneously transmit and receive data. It's a fundamental technology that allows for increased throughput without expanding the frequency range.
In older standards, such as SU-MIMO (Single User Multiple Access Mode), a router could only communicate with one device at a time, switching between them at incredible speeds. This created a queue of requests, especially when many devices were connected to the network.
With the advent of the 802.11ac Wave 2 and 802.11ax standards, MU-MIMO technology was introduced. It allows a router to transmit data to multiple devices simultaneously. This doesn't increase the peak speed for a single client, but it significantly improves overall network throughput in congested environments.
What is the difference between 2x2 and 4x4 MIMO?
The numbers indicate the number of transmitting and receiving antennas. A 2x2 configuration means two antennas for transmitting and two for receiving, doubling the speed compared to a single antenna. 4x4 quadruples the throughput but requires a corresponding number of antennas in the client device (smartphone or laptop).
It's important to understand that connection speed is always determined by the weakest section of the chain. If you have a powerful router with 8 antennas, but your smartphone only supports 1 antenna (1x1), your speed will be limited by the phone's capabilities.
Factors that reduce actual connection speed
Even with top-of-the-line hardware, users often experience slow speeds. There can be many reasons, most of which stem from environmental issues or improper settings.
Physical obstacles are the main enemy of radio signals. Concrete walls with rebar, mirrors, aquariums, and even tree foliage outside the window can absorb or reflect signals. The 5 GHz band, which has less penetration but higher speeds, is particularly vulnerable.
Interference from household appliances also plays a role. Microwave ovens operating at 2.4 GHz can completely jam the WiFi signal while they're operating. Cordless phones and Bluetooth headsets also contribute to overall noise.
- 📡 Airtime congestion: In apartment buildings, dozens of neighboring routers create a "mess" of signals, forcing your router to constantly jump between channels.
- 📉 Outdated drivers: The network adapter software in your computer may not function properly, not using the full potential of the hardware.
- 🔌 Cable connection: Sometimes the problem is not with WiFi, but with an old provider cable or a router port, which is limited to 100 Mbps (Fast Ethernet).
To diagnose problems, you can use specialized WiFi analyzer apps on your smartphone. They will show channel load and signal strength at different points in the apartment.
☑️ Checking speed reduction factors
How to measure and increase bandwidth
To get objective data on your connection speed, relying on your own experience isn't enough. You need to measure it using specialized services like Speedtest or Fast.com.
When testing, it's important to get as close to the router as possible to eliminate the impact of distance. It's also recommended to disconnect other devices from the network to prevent them from consuming data during testing. Compare the results for 2.4 GHz and 5 GHz frequencies—the difference can be significant.
If your speed isn't working, start by rebooting your router. This is a simple but often effective tip. Next, try changing the broadcast channel to a less congested one. In your router settings, find the wireless section and select a channel manually, avoiding the "Auto" option.
⚠️ Attention: Router interfaces from different manufacturers (TP-Link, ASUS, Keenetic, MikroTik) may vary. Look for sections labeled "Wireless," "Wi-Fi," or "Wireless Network." If you're unsure of your settings, it's best to take a screenshot of the current settings before making any changes.
In extreme cases, if the router is old and doesn't support modern standards (for example, only 802.11n), no amount of configuration will overcome the physical limitations of the hardware. In this case, the only solution is to replace the access point with a more powerful model.
Why is WiFi speed always slower than cable speed?
Wireless media are less reliable than copper cables. WiFi protocols spend a significant amount of time on error checking, resending lost packets, and signaling. Furthermore, the half-duplex mode prevents data from being transmitted and received simultaneously, theoretically halving the maximum throughput.
Does the number of connected devices affect the speed of one client?
Yes, it does. Although modern technologies (MU-MIMO) help distribute the stream, the total airtime is divided among all active users. If one device is downloading torrents at full speed, the others will only have a queue to transmit small data packets.
Can a provider limit WiFi speed?
Your ISP limits your speed at the entrance to your home (WAN port). Within your local network (WiFi), only your router sets the limits. However, if the router is weak and its processor can't handle traffic encryption or routing, it can throttle your speed, creating...