After a 7-year corporate stint, Tanveer found his love for writing and tech too much to resist. An MBA in Marketing and the owner of a PC building business, he writes on PC hardware, technology, and Windows. When not scouring the web for ideas, he can be found building PCs, watching anime, or playing Smash Karts on his RTX 3080 (sigh).
Most people rely on a quick speed test on Speedtest.net or Fast.com to gauge the status of their Wi-Fi connection. These sites are used mostly when users are facing unexplained latency on their Wi-Fi, but the download/upload speeds shown on speed tests may still show that nothing's wrong. Internet speed tests are good for confirming that your ISP isn't throttling your connection, but it doesn't shed much light on anything else.
Bandwidth is just a small part of your Wi-Fi. Your wireless connection is affected by several other variables that are outside the purview of a conventional speed test. Factors like airtime congestion, radio interference, and bufferbloat are usually hidden when you run a speed test on your smartphone. A healthy speed test might be hiding the real issues with your Wi-Fi connection.
Speed tests depict only a tiny segment of your connection
The bulk of the view is hidden
A quick speed test feels convenient, and usually shows the maximum download speed provided by your ISP, but it's useless as far as a comprehensive network test is concerned. For context, it measures the state of the connection only between your phone and the router. Even if you see stellar test results, this only tells you one thing: that your ISP is delivering what it promised.
What's happening past that point is usually not covered in a speed test. Since most speed tests simply send sustained transfers (several hundred MBs of data) to the local server or CDNs, they don't represent real workloads on a home network. The test server is usually uncongested and has few hops, so you're most likely to get positive results.
What happens when multiple devices are transmitting simultaneously? What about real-life workloads where your phone needs to use multiple DNS lookups to source dozens of objects for a single webpage or navigate long-winded paths to a website? Your phone's speed test doesn't tell you the expected quality of your Wi-Fi when visiting random websites, connecting to global game servers, or browsing social media apps.
It doesn't tell you what's happening inside your network
You need to figure that out yourself
Your speed test shows download and upload speeds between the router and your phone. It may also show you the ping and jitter involved, but that still doesn't tell you anything about the myriad number of other factors affecting your wireless network. Unlike a wired connection, your Wi-Fi is subject to radio interference, airtime congestion, bufferbloat, among other things.
Getting excellent results on a speed test doesn't tell you if your router's location is optimum or whether you're using the right channel and channel width. Interference only really shows up when you fire up a latency-sensitive workload on your phone, such as gaming, video calling, and video streaming.
Airtime congestion is yet another hidden phenomenon that routinely affects most Wi-Fi connections. Unless you've enabled Airtime Fairness to give every device the same amount of time to transmit on the network, home automation devices and other slow clients can hog more airtime, leaving little for your high-priority devices.
Then, there's bufferbloat, which happens when your router maintains a large queue of data packets instead of dropping them, leading to a sluggish Wi-Fi as your devices keep waiting in line. You can run a bufferbloat test on your phone to get a score for your network and enable SQM (Smart Queue Management) if you get anything other than a "A" or "B."
A good speed test ignores a slow DNS server
Change your DNS server today
Another aspect that is ignored by speed tests is the DNS server your phone is using to resolve domain names. When you type in a website name like "google.com," your DNS server resolves it into an IP address to establish the connection. This process should take a fraction of a second, usually under 50ms, but if your ISP's default DNS server is slow or congested, this can go up to several hundred milliseconds.
A connection reporting 300 or 500 Mbps bandwidth on your phone can still feel sluggish if it's routing through a slow DNS server, since the delay kicks in even before the data starts moving. It's worth running a DNS speed test to find the fastest DNS servers for your location and pick one that's free to use. Switching from your ISP's default DNS doesn't just make your Wi-Fi snappier; it also improves your network privacy.
Slow DNS lookups on your phone can result in a tangibly slow connection when you're pulling from several domains to render a single webpage. It's one of the most ignored aspects of a home network as most people keep using their ISP's slow DNS without thinking about it.
Stop relying on Wi-Fi speed tests to judge your connection
It's easy to glance at a speed test and declare your Wi-Fi "just fine," but there's a lot more going on underneath that speed tests just don't show. Your Wi-Fi is affected by fluctuating interference, router bufferbloat, airtime congestion, and many other factors. Diagnosing and fixing them will fix your Wi-Fi, despite what a speed test might show.