Internet connection speed PC vs PS3

I was watching Netflix on my PS3 and I had the details about what quality was streaming up on screen. When I watch Netflix on it I get 1080p SuperHD. Lovely, I like that. But when I watch it on my iMac(mid2011 21.5") I don't get HD content hardly at all. They're both connected wirelessly and they're both sitting next to each other (the PS3 is actually about a foot further away from the router)

I was just wondering, why is the PS3 so much faster?