The speed that can be achieved when using a service on your smartphone, PC, tablet etc. depends on two factors:
The connection between your device and the Internet-Box.
The performance of this connection can be improved by optimising your home network (for example, by using the latest CAT 6 cables, faster switches and WLAN boxes). In the end, however, the device will be limited by the maximum speed it is able to achieve – many older laptops, for example, will only be able to achieve speeds of 100 Mbit/s over the Ethernet interface.
The connection between your Internet-Box and the Internet destination
As well as your Internet subscription, your Internet performance also depends on other factors, such as network congestion. If you want to download a file from the servers of an online storage service provider, for example, and that service provider only provides 10 Mbit/s bandwidth for the download, the perceived performance is only 10 Mbit/s, although your line could reach much higher speeds.
Also note that some of the data (approximately 15%) is there to ensure transmission quality. This reserved bandwidth cannot be used to transmit content (such as photos, movies or music). 8 Gbit/s is the maximum usable speed for all devices in the home network together (including WLAN).
The maximum achievable speed for one device over the fastest Ethernet connection (Internet-Box 4) is 8 Gbit/s. When uploading and downloading simultaneously, the speed may be limited to 6 Gbit/s.