I use a 1080p monitor and what I’ve noticed is that once creators start uploading 4k content the 1080p version that I watch on fullscreen has more artifacting than when they only uploaded in 1080p.
Did you notice that as well?
Watching in 1440p on a 1080p monitor results in a much better image, to the detriment of theoretically less sharper image and a lot higher CPU usage.
YouTube compresses the shit out of 1080p content. Any video that has a lot of movement will look like trash at 1080p. Even if you’re on a lower resolution monitor, the higher bit rate of higher resolution videos will look better. It’s all very stupid on our end, but I assume it saves them a ton on bandwidth.
YouTube automatically generate videos in lower resolution of the one uploaded.
So when you watch a 4k video and switch to 1080, you are no longer watching the original video but a re-encoded one by YouTube itself which could have more artifacts since it’s resized and compressed.I dunno the exact specs (like bit rate, etc.), someone will probably add them in another reply.