Yeah... I've got a small anecdote. I find that I write better code on lower resolution screens. Right now, I'm on a 1440x900 display at 75 dpi. And it's annoying, for sure. But it keeps my code concise and well-organized. It forces you develop your code around a mental model, instead of a visual model.
I find that at 4K, my code starts spreading out -- horizontally and vertically. That's fine when you're writing it, but when you come back to it months later, it's so hard to comprehend that much information all at once IMO. It's weird. And I might not be explaining it properly.
If you were to write your code on an 800x600 display, you would make sure that every function did not go over 800 vertical pixels. It would probably give you a headache if you did.
I can look at code and almost immediately tell that it was written on a 4K display. Oftentimes, everything is spread out and chained obtusely.
Completely different game for web dev though -- having the browser side by side with your code helps.
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Also, 4:3 is awesome for code. All I need is two, side-by-side panes of 80-column text :)
16:9 has me glancing left to right too much.