The video quality on Vessel is really really bad, it doesn't even look like 1080p, so watching on a 4K monitor is unbearable. I really hope this gets fixed fast, this is a major technological step down.
Example:
Okay that makes sense. I have always understood it as cpu coolers remove heat, and therefore it can not get below the ambient room temperature.
Ontopic: If your motherboard doesn't support adjusting fan speed, you may some form of hardware fan controller.