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I just wanted to share something that might help some people out if they're having a similar issue with their broadband connection that I've had, my connection has been dropping out whenever I had more than one device connected to the router, whether it was via wifi or ethernet cable it didn't matter, if another device connected to the network to use the internet then it was just a car crash for all devices involved, if only one device was connected then it was fine for me.
If you connect to the router using a PC at 192.168.1.1, enter your password and all that, change to expert mode, go to the settings tab and click "QoS Control" at the bottom of the list, in there you have the option to limit the bandwidth by device, make sure you connect all of the devices that you have to the wifi network so you can select them from the drop down, I found that if I allocated a % to each device, say 50% for PCs, TV & consoles, 30% for mobiles, something that means that any one device doesn't take 100% of the bandwidth, that seems to have sorted the problem out for me and I could then connect multiple devices to the network without everything locking up.
So it seems like my router is having problems sharing the connection out to different devices, I shouldn't have to manually limit each device to a certain %, the router really should be doing that for me, that's its job! Maybe I have a bad router, I don't know, but regardless if you're having the same problem then that might save you going out and buying a new router immediately like I was planning on doing, so I thought I'd post it up in case it helps any of you like it's helped me.