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okay thank you I was worried that I would have to return it and wait another 1 week to get another one :D
 
I can play it at 1440p, but get an error from YouTube when I switch to 4K. Problem is with YouTube, not the computer.

Very much so. I just ripped the video locally and played it back NP in MPC-HT
 
To be honest with you mate, that file is compressed to hell, its covered in macroblocks and it looks like ***** which will happen if you try to watch it through Youtube.

If you're looking for some real 4k content to play back on a 4k monitor, try this movie you can download for free:
http://tearsofsteel.org
 
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