I've been playing with Netflix on my 3 PCs for the last 2 weeks, under WMC and Internet Explorer. I have an early Atom netbook, an E-350 HTPC and an Athlon II X4 645 desktop. We all know about the problems with Netflix/Silverlight so I won't go into that other than to say that I have achieved smooth playback at bit rates of 1050 on the Atom, 1750 on the E-350 and 3600 on the Athlon.
One thing I have noticed that I can't find mentioned on the internet is that regardless of the PC I am using, A/V Stats shows on the //HTTP line that when running Netflix under IE, Silverlight 5 is referenced:
while when running under WMC, Silverlight 4 appears
I can only assume this proves that the WMC Netflix add-on has not yet been updated to utilize the capabilities of Silverlight 5.
Has anyone else noticed this?