Hi.
I have the very same problem. I always liked Opera but ever since they switched to WebKit it is simply not the same.
And now, among other issues, it DOES mess up the internet connection. Pages sudenly stop loading and shortly after entire traffic on my PC is down, not only WWW. Everything. Then I need to wait a bit or restart the router. During down time, other devices work normally.
It almost seems like Opera forces Windows to think that IP lease expired and forces it to renew it (but without rush). It happens in random intervals.
Do not listen to the chap saying it's drivers issues. It is not. If it was then there would be a global problem with connectivity. Tested. Other browsers or services work absolutely fine. Thas stops quickly once I launch Opera. It goes back to normal when I stop using Opera either by shutting it down or simply leaving it alone and not (re)loading any page (or by killing it with frustration).
I must admit that I have not tested it with Chrome. If anyone does, post the findings here please. I hate Chrome with passion therefore noone will talk me into testing it. I rather switch to Firefox. Unless this bug gets fixed.
Regards.