When you first get connected, the system has to determine the max speed you can get a stable connection on. So it will typically start you off conservatively, and if that's ok, try something faster. If it is getting too many errors it will drop the speed down a bit. Each time it changes the speed, it resets the router. After a short period the speed should stabilise, and the resets will become rarer, perhaps every day or two. However if there is a fault on the wiring, so that the speed it attains is nowhere near what it should be, or if the problem is intermittent, so that a previously stable connection becomes unstable, then the resets will be more often
I had previously been on a 40/10 contract with another supplier I had 34 Mb/s with a connection that dropped occasionally.. When I switched to Plusnet on 80/20, (with an expected min download speed of 70Mb/s) my connection was mainly 26Mb/s (as indicated on the "connection" tab under the advanced settings on the router web interface). It would switch up to around 50Mb/s or so, and a minute or two later drop it back down again. It was doing that several times an hour before learning that it really couldn't supply better than 26Mb/s. It turned out that one of my line filters was defective, and the phone line was interfering. On replacing the filter, the connection was established at 68 Mb/s. 4 days later and 2 or 3 resets later, it is up to 72Mb/s
So, my advice is:
if you are getting close to your expected speed, it should settle down over a couple of days. If it doesn't, then you need to take it up with Plusnet tech support. If you aren't getting your expected speed, then , if you haven't done so already, you will need to go through the standard fault finding - using the master socket and filter with all extensions disconnected to see if that gives you a better speed, before involving Plusnet
