A router restart does many things and can often resolve most connection issues. We’d recommend restarting your router if you notice your speed dropping since this might be due to the router becoming less responsive over time, perhaps because of memory leaks which slow down the system.
The router operates like a computer in some ways, with it's own memory and cache. Restarting the router also empties the DNS cache inside of it. There are times when a DNS cache contains out of date page info and clearing it can make things work better.
When you restart a router it also requests a new IP address from our server which can help with connectivity issues.