As it turns out, while Tweetdeck has sped up considerably, Youtube is continuing to suffer issues. I have turned off all my extensions just to be sure, but on occasion Youtube will just stop, stutter, and buffer indefinitely, or the audio will play and the video will not. Again, this doesn't happen on my other browsers, and this happens no matter what extensions I have on.
Vivaldi: Snapshot 1.16.1259.3 (Official Build) (64-bit)
OS: Windows 10