Why does the built-in file copy service work strangely in OS Windows 8.1?

Question

Data transfer

OS Windows 8.1 somehow strangely works the built-in file copy service, for example, copying files over a Wi-Fi connection:

As you can see, there is a big difference in speed.
Moreover, if you pause copying, the connection speed does not drop, then wait a bit and start copying again, then at the same second the copying speed, firstly, will increase sharply in real time, and secondly, the visual number itself will increase:

Apparently, standard file copying tools do not very effective, tell me who how to get out of the situation?
Or maybe I have a problem with Wi-Fi?
How do you check the real data transfer speed over a Wi-Fi connection?

Answer 1

So after all, the Wi-Fi speed is given in megabits, and the copy speed is in megabytes. If you divide that 52.5 Mbit/s by 8, you get about 6.6 MB/s, pretty close.

Answer 2

The speed is usually here .
There is a similar situation, possible problems are described there.

Answer 3

Yes, I calmly always squeezed out nonsense by simply copying 100 megabytes per second in Windows.
Try to copy in the same total commander well, without Wi-Fi, grab the cable and try it too.