So you have a personal ISP, that does not serve any customer but yourself? Lucky. Just fyi, ISPs do not have unlimited Bandwidth for everyone connected to its service.
also,
Well now. This guy looks a PRIME candidate for screwing with your Internet. Disable THAT for a few days and see where it gets you.cFosSpeed - Internet Acceleration with Traffic Shaping and bandwidth management.
If it uses profiling to determine your internet habits, it may have accidently decided to throttle XIV and give that to Skype.
Skype is also known to consume ones bandwidth at times due to the way the Skype servers will use its Users bandwidth to improve others service.