The Full Fibre 900 package often means that customers do achieve the speeds that they think they should (obviously around 900Mbps). This is very often not an issue or design of the 900Mbps service, but the connection between their devices and the router. The Wi-Fi network adapters in these devices often cannot deliver speeds as fast as the fibre service can.
Take the example of some older Wi-Fi 5 (802.11ac) adapters that might work at speeds up to 433Mbps, when used in a perfect wireless environment, which most homes are not. When an internet speed test is performed, the speed achieved is down to the slowest link in the chain, namely the 433Mbps Wi-Fi adapter. Speed tests in this case might achieve somewhere around 400Mbps or less.
Older Ethernet connections can suffer as well. If a device only supports the 10/100Mbps standard, not the normal 1000M (1Gbps) or even the newer 2.5Gbps available on some desktop PCs, they are likely to only record 100Mbps on a speed test.
To get the 900Mbps on a speed test, that device must either have a minimum of a 1Gbps Ethernet connection or if wireless, a much faster WiFi adapter. This would be a higher specification Wi-Fi 5 (802.11ac) or Wi-Fi 6 (802.11ax) adapter. Even so, at these wireless speeds, signal quality must be near perfect (signal strength with very little Wi-Fi interference).
