This post hardly matters now as Netflix is discontinuing the Windows Media Center Netflix App on September 15th 2015. Since reinstalling Windows and Media Center on my HTPC a few months ago I have been getting terrible vertical sync/screen tearing issues in the WMC Netflix App.
I tried several suggestions related to video drivers, Silverlight versions, etc. but none made any difference. I don't get tearing when watching videos, DVDs, Live TV or YouTube. The issue only occurs in the WMC Netflix app. It makes some videos unbearable.
My HTPC doesn't have the greatest specs so after installing I disabled extra services, removed wallpapers and turned off Aero. I was hoping this would free up memory and CPU and GPU time allowing WMC to perform better.
After the announcement that Windows 10 would not provide Media Center I have been looking for new DVR software. Yesterday I decided to MediaPortal a spin. During the installation it recommended enabling Aero to help avoid screen tearing. Well that immediately made me think of my horrific Netflix performance. I enabled Aero and, how about that, Netflix works perfectly now!
Dang It! It's been months and I never came across a suggestion that Aero could affect Silverlight's video rendering.
Ah well, at least I get to enjoy one final month of tear free WMC Netflix viewing!