Its actually funny, I used to have a similar issue with my Vita. It used to pretty much hog all the bandwidth fro some reason when I played online or used the PSN in general. No other laptop or smartphone connection was possible, on a fairly good router and internet connection that could usually easily support 4-5 laptops with constant connection. Then after an update it simply stopped and it worked as it should have.
I didn't notice this with my PS4 though. I can easily play online, while my girlfriend is working from her PC, my PC is downloading some movies or games and my brother/sister/mother/whoever uses it to browse the net from his/her smartphone.
Could this be some sort of compatibility issue with the PS firmware and the router you might be using? Was this always present?
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