UserAgent: Mozilla/5.0 (X11; CrOS x86_64 8530.93.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.144 Safari/537.36
Platform: 8530.93.0 (Official Build) stable-channel zako

Example URL:

Steps to reproduce the problem:
Load YouTube video https://www.youtube.com/watch?v=iNJdPyoqt8U with 4k.

What is the expected behavior?
Smooth playback

What went wrong?
Video stutters as it is played back.

Does it occur on multiple sites: N/A

Is it a problem with a plugin? N/A 

Did this work before? N/A 

Does this work in other browsers? N/A 

Chrome version: 53.0.2785.144  Channel: stable
OS Version: 8530.93.0
Flash Version: Shockwave Flash 23.0 r0

Force playback with chrome https://chrome.google.com/webstore/detail/disable-youtube-html5-pla/enmofgaijnbjpblfljopnpdogpldapoc/related?hl=en

resolves the issue