I recently commissioned a new BT Fibre 100mb circuit which hooks up to a Draytek router. When visiting large site like news.bbc.co.uk then request just sits there for about 8 seconds and then the page appears. When I do the same on my laptop using a 4g signal, the website pops up within a second. After further testing I can see the delay happens to most pages on the BT Fibre connection. Ive change the DNS servers on the router to use google DNS thinking it might be something to do with BT Dns Servers not being fast enough but this has not made any difference. Ive also flashed the router to the latest firmware.
The PC's are connected to the network by a 1gb Cisco network switch.
I also carried out a test on speedtest.net and got a ping time of 9ms, upload 99.6mb and download 99.8mb so the connection seems fine??
How best can I troubleshoot this issue to work out where the problem is coming from?