You can take a speed test at speedtest.net. We recommend that you take the test by connecting the computer to a network cable, as this is the technology that allows the highest speed, and this is the only device connected to the network.
Speed ​​is guaranteed by cable, Wi-Fi will be reduced. The result will always be correct depending on whether we use a suitable network cable (category 5e or higher) and the device with which we connect can reach these speeds (gigabyte network card).