This is a little geeky but BreakItDownBlog did some analysis on a strange problem he was having. When he viewed Netflix video on the 360 it was coming through without jitters or problems but once he tried viewing it on his PC it was failing catastrophically.
A little digging discovered that although the downstream was running at 7 mbps, the stream was downloading at about 52 kbps. Writer Riyad posits that this is to prevent overloading of bandwidth at Netflix and the high speed downloads on 360 are basically a quality-of-service situation where they have to supply a certain sort of experience or face eviction. I’ve noticed horrible quality PC streaming most times I’ve tried using the service.