[Kushan]

There's a contradiction in the story here - you say the 2Ghz falls over and the PS3 uses that. However you also say that the PS3 is connected via Homeplugs. It can't be both, unless I'm misunderstanding something about homeplugs, they're not running on a specific frequency or anything like that.

Is it possible that although you've plugged the PS3 into a homeplug, you're still connecting via wireless? It'd be worth double checking the PS3's network connection and ensure that it's ethernet.