Why isn’t my Wi-Fi as fast as advertised?

Q&A of functional explanation or specification parameters
Updated 11-19-2021 09:39:07 AM FAQ view icon40852

The pending wireless standard 802.11ax (Wi-Fi 6) is one of the most anticipated things in 2019 for its greatly-improved capacity of higher data rate and overall network throughput, particularly in high- density scenarios.



Wi-Fi 4

Wi-Fi 5

Wi-Fi 6

Frequency bands

2.4 GHz and 5 GHz

5 GHz

2.4 GHz and 5 GHz

Maximum data rate

150 Mbps

3.5 Gbps*

9.6 Gbps*

Highest subcarrier modulation




Spatial streams




Underlying technology

IEEE 802.11n

IEEE 802.11ac

IEEE 802.11ax

*Depending upon numbers of spatial streams and channel used.

Adapted from Wi-Fi CERTIFIED 6™ Highlights, Wi-Fi Alliance

When someone goes to a store or shops online for a new router, it’s helpful to consider the data. However, while Wi-Fi technology has improved by leaps and bounds, sometimes the speeds aren’t as fast as expected. Many people, especially rank-and-file users, are still confused about Wi-Fi speed, and one of the most frequent questions is, “Why isn’t my Wi-Fi as fast as advertised?” To answer that question, there are a few things you need to know, like...

What are the data rate and throughput?

Normally, the industry uses the data rate and throughput values as they are good measurements for evaluating wireless network capability. Data rate and throughput are similar concepts, but they vary slightly.

According to the WFA (Wi-Fi Alliance), data rate (or physical rate) is the maximum wireless associated rate between the router and a client through a wireless link. It is the internal WLAN (Wireless Local Area Networks) connection speed, but not the actual internet speed. Influenced by wireless modes, distance, or other interference factors, the transmission speed is typically 75 percent or less of the data rate in a real-world scenario.

That sounds like a shame, but on the other hand, unveils that data rate can be regarded as an important measurement to estimate the maximum transmission capability of your wireless connection. To be specific, to know if your wireless network is well-configured.

Compared to data rate, throughput might be a more technical, professional measurement. Also according to the WFA, throughput is the transmission capability that is available to applications after the overhead required to address the needs of upper layer protocols has been addressed. By definition, throughput is a subset of a device’s data rate.

To clarify, wireless transmission can be thought of like delivering a package. If you want to send a beautiful crystal to your friend, the package would include not only the crystal but also packaging, shock-proofing materials, address information, and other extra things that help ensure safe delivery. Wireless transmission works like that. There is always extra overhead to ensure security and stability or other beneficial purposes in data transmission. In the former example, the package delivered in one time can be regarded as “data rate” and the crystal is the real “throughput” that you want to send.

What factors affect my actual Wi-Fi Speed?

The wireless network is by nature prone to interference and other severe problems. That is the main reason why the actual wireless data rate and throughput are not guaranteed and always vary when exposed to different environments. Furthermore, the disparity between theoretical data rate and actual wireless transmission rate comes from many common factors in our daily life.

  • Environment and Distance

The attenuation of wireless signals during transmission is inevitable, while distance and obstacles (and also building material) can exacerbate it. The most typical example is a 5 GHz Wi-Fi signal. Unlike a 2.4 GHz signal, it is hard for a  5 GHz signal to penetrate solid objects and performance might deteriorate more rapidly as distance increases.

What You Can Do: Place the router in a central location or where you use electronic devices most rather than a distant corner.

  • Clients
  1. The Number of connected devices. An intrinsic feature of wireless networks is that the connection is always shared and seized by various devices. Therefore, Wi-Fi performance decreases when too many clients are connected to the same router.

What You Can Do: Check the recommended amount of connected clients for your router and don’t add too many clients into your wireless network.

  1. Limitation from the clients with lower speeds. Though the new Wi-Fi 6 strives to solve this problem, the issue can be hardly ended until Wi-Fi 6 devices are in popular use. Communication between a router and its clients happens one at a time. When one client is communicating with the router, the other clients have to wait until the transmission is finished. This is aimed to prevent signal interference. Due to this, a client with low transmission speed and poor performance would limit the total throughput of the entire wireless network by hogging too much time for its own transmission.

What You Can Do: Avoid using too many legacy clients that only support the old wireless standard. Toggle on the Airtime Fairness feature (if equipped) on your TP-Link router to make time allocation more efficient.

  • Other Interference

Wireless spectrum resources are limited and shared by different clients, so interference is common everywhere. It can come from a neighbor’s wireless network, a microwave close to the router, devices using Bluetooth or USB 3.0 (which both work in the same frequency with 2.4 GHz Wi-Fi), etc..

What You Can Do: Avoid using crowded Wi-Fi channels and frequencies. To do so, change to a new channel in your wireless settings or reconnect to a 5 GHz network.

  • Other Limitations
  1. The bandwidth provided by your ISP (Internet Service Provider). When surfing on the internet, the actual maximum internet speed is also related to your ISP Speed.
  2. Incompetent power supply. This leads to the poor performance of the router.

Is it necessary to have a router with a higher data rate?

It depends. In fact, over decades of effort—especially breakthroughs in recent years—most people can meet their needs without spending too much money on pursuing a  high-specification router.

But generally, buying a router with higher data is recommended if you are fond of new-tech and the latest wireless devices and have a great demand for higher data transmission. For example, if you get a smartphone that supports Wi-Fi 6, you would need a Wi-Fi 6 router to make the most of the transmission speed. Besides, the higher data rate means increased robustness for your speed. In the same environment and under the same conditions, a higher data rate provides better wireless performance.

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