basically we're saying Don't be fooled by the speed on the Box you will never get that kind of speed.
For instance My powerline adatpors say they are 200Mbit/s on the box.
I have 3 of them , IF 2 are on i can max out my 22Mbit/s Broadband.
As soon as the 3rd one is turned on I only get 10 - 15Mbit/s even though nothing is using the other 5-6Mbit of bandwidth.
Same sort of speed with PC > PC transfers over my Internal network...
The Numbers the Manufacturers quote are always in Ideal conditions (which lets face it who has those
) Overheads also reduce the speed (e.g information that they need to transfer to maintain the link, pass data between eachother.etc)