For me the problem lies at BT’s oversaturated door.
I am no IT guy but have learnt along the way. Have a ASUS Wi-Fi 6e router. Four high end computers are connected to the router which has 2.5g Ethernet through a 2.5 g switch. Also two XBOX series X and one PS5 connected at 1g.
Steam downloads, XBOX and PS5 always achieved close to our 900Mbps download speed via Ethernet and Wi-Fi 6e. Now the very best speeds I achieve are around the 400-450 mark. My router confirms connection to the Openreach Modem at full speed.
For me that’s enough tests all settings on all software are set for no bandwidth limiting and QOS on the router is set to best performance. Talking about a quad core router and 1gb of ram with no ISP router in the way.
For a laugh I removed my router and used the BT router and the download is very slightly higher. Maxing out at about 480 to 500 Mbps. A neighbour who as a great deal of IT experience agrees it must be on BT’s side. They have OGI internet and I connected a high end laptop to his router via Ethernet and 880-890 Mbps. Same laptop on my network tops out at around 480 Mbps.
My speedtests always report 900Mbps or close enough on Ethernet and on wifi. Usually get around 800Mbps on my iPhone 14 pro and around 880Mbps to 900Mbps on my pc with Ethernet.
I am by no means a expect in IT so don’t know what other tests are available. Any advice would be helpful.