You sir have saved my sanity !! So far turning off the Port Scans option in BitDefender seems to be working.
I test-downloaded a big file earlier, went into a game and there was no frame-rate...

Yeah mine does that. I've deleted all the unused devices from the gateway now. Such a crap box it is but we have to use it. So this is why I`ll buy a Draytek now and connect it to my gateway which...

Yeah I would remember that so no it's not set up that way :)

It's not in bridge mode yet, just operating as a standard router. But my idea was to buy my own better router and then use theirs in...

Will check that as soon as I get home. I am starting to think now that it's a router issue and I have such a crap router too. One that is given by the ISP. I may decide to just grab a Draytek...

Well this is a strange one.
I guess it started when I disabled my onboard LAN and installed a third party network card in my PC and couldn't assign it the same IP as the one the previous card had....