I recently experienced a speed drop - down from my regular >35 Mb/s to around 5Mb/s. Plusnet coiuld find no problem with the supply to my router. Various re-boots and switching out of devices under direction from the Plusnet help desk had no impact.
The help desk phone call having ended, I then tried changing the broadcast band of the wireless network card from 2.4GHz to 5Ghz via Windows settings (suspecting the cause might be traffic congestion on the default 2.4GHz band). Bingo - device connection speed came back to normal. I then changed the wireless card back to 2.4GHz, again achieving a positive result with speeds back up to 35Gb/s.
Further research suggests that this action has the effect of clearing the wireless DNS cache. (an area of the tech I am completely unfamiliar with)
This ultimately proved to be a very quick fix, well worth a try if you experience an apparent drop in connection speed.
