Are you by any chance connecting to a 5 GHz network? I have had, and others have mentioned as well, reliability issues when connecting at 5 GHz. If you can connect to the 2.4 GHz band instead, this may "miraculously" fix your issues.
I've even had issues with our Roku 3 buffering and blacking out entirely when on our 5 GHz band. I don't understand why this is happening, becuase it seems a fairly new annoyance, and obviously isn't limited to just my G4. Historically, I've split all of our stuff to try and keep things moving smoothly on the network. Devices that were stationary and close to the router got 5 GHz, stuff that went upsatirs a lot got 2.4 for the longer reach. 5 GHz now seems too unreliable to use for some stuff.
Anyway, try switching to 2.4 GHz (your router may not indicate 2.4 GHz but will indicate 5 GHz...so its the other one). Good luck.