How do you mean sluggish? As in the 24 FPS vs 60 FPS or that the actual video playback is sluggish? It's pushing a very high bitrate and I can see on my network card stats that it's running 20-35 Megabits per second of data when I try to watch this in 1440p. Also FYI my computer at work was not able to play back the KZfaq video in neither 1440p nor 2160p :o So yeah, another reason why I will go for 1080p down-sample.

Well, it is not 'terrible,' but at high refresh rates, 24hz is very noticeable. I could tell from the instant the video started. Just a minor annoyance I suppose. Not a big deal. I don't think most people have a monitor capable of 1440p and a 144hz refresh rate. When you become used to high refresh rates, you begin to notice how inferior lower refresh rates are. Do you know what I mean?

Does it have to do with your internet at work being shitey, or the fact that your work PC is a potato (no offence)? I mean, yeah. A Dell from 2005 could probably render a heavily compressed KZfaq video at 1440p and 2160p without problems, if the internet is decent (unlikely to be a problem with Ethernet). I remember a while ago there was this experimental video that could be upscaled to 8K. This was probably two years ago, and whilst my computer has always been very far from being a potato (I place great emphasis on continuous upgrades), I had zero problems rendering a compressed 8K video. At that point, my internet actually became the bottleneck, not the capabilities of my PC.

Right. I see what you mean. But in that case it should be the same if you watch a movie/BluRay that is 24p as well? But, probably more that you are used to very high FPS and refreshrate than my video being very crappy :D

Haha. The internet is fine. We have 1Gigabit per second internet connection at work (Sweden!). The computer however is like 5 years old so :D