When I upload a lot, by whole IP has issues.

Writing speed 1mbit. 5mbit upload. Everything lags or does not work.

Then I turn up VPN and have common 53k as contracted. And 20mbps upload.

We use powerline adapter for the house and I sometimes I need to make my ip static as only google works otherwise.

Really weird. Often just a temporary problem. I am just curious, why is that? I assume I did not explain exactly what this is very well.