Firmware LG-RDK_7.6.15-2306.5 for the HUB 5, is breaking the 2.5G port. The 1G ports still works at up to 1,000 Mbits ie 960 on Speedtest.
If you want the avertised 1130 you need 2.5G devices, including a 2.5G Managed switch, EEE off by default. which gets around 1140.
Use the virgin recommended Sam knows speed website to check. You need the virgin link for this.
It does not matter if your using Normal or Modem mode, both are affected.
Basically EEE is Energy Efficient Ethernet, which puts connected (wired) devices into low pwoer state when not used for a period of time. Devices are not comming back out of this state. This setting saved sevral GW/Hr when rolled out in the US.
By using a Managed switch which enables users to turn EEE off and on, you can control this. I leave mine turned off. Or turn off EEE on your network device if connected direct to the 2.5G port.
Virgin do not support user purchased devices connected to the bub.