So you (one person) link one that's broken and save us (the whole forum) having to search for some on youtube. People are lazy and you are the one asking for help. So link something that is known to be broken for you and people can test and verify.
I'm pretty sure it's going to be either a broken plugin issue or AMD video drivers sucking ass.
chrome://plugins/ to disable all plugins EXCEPT "C:\Program Files (x86)\Google\Chrome\Application\40.0.2214.111\PepperFlash\pepflashplayer.dll"
chrome://extensions/ to disable all extensions.
Tested Totalbiscuits videos at 1080 fullscreen 60. All fine here with an Nvidia card. As someone said Youtube has moved to the HTML5 player now so the pepflashplayer is only called for some legacy content and shouldn't be an issue anyway. The external flash player that you may have installed should be disabled or uninstalled for testing.