Background

In my current role, we sometimes receive complaints about the Wi-Fi being slow or not working properly. When we ask what the issue is, we’re often sent responses referring to speed test results only that are supposed to serve as the definitive proof that something’s wrong with the Wi-Fi. What our user base often doesn’t understand is that there are many variables when it comes to speed tests in general, but when running these speed tests while connected to Wi-Fi, even more variables exist. Let me try to explain.

Whether it be wired or Wi-Fi, there are theoretical and real-world throughput maximums in networking that are affected by a number of things. For example, even when you have a 1 Gbps wired connection, chances are you’ll never get full 1 Gbps line-rate speeds in a raw throughput test due to at minimum, the overhead needed to put bits onto the wire, not to mention whether the latency and TCP Window Size (if using TCP) can support the line-rate speed. Latency and the TCP Window Size are two things I’ll come back to in more detail later.

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