The way I think it, it’s possible a really small number of GPUs would be enough to render the framebuffer, you’d just need an army of low-power graphics units to receive the data and render it on screens.
Having a high-power GPU for every screen is definitely a loss unless the render job is distributed really well and there’s also people around to admire the results at the distance where the pixel differences no longer matter. Which is to say, not here.
A “hbox” in TeX is a horizontal box. In 99% cases when laying out text, it’s a line of text. “Underfull hbox” means “I couldn’t stretch the content of this line far enough, so it will look janky as f due to the increased spacing”. “Overfull hbox” means “Well, I tried my best to hyphenate and line-terminate, but this word will stick out of the margin and will look stupid as f.”
Most of the time this is caused by a word that auto hyphenation can’t deal with. You need to add a manual hyphenation exception. I can’t remember how to do that, sorry, because it’s been a while and also I’m mildly drunk, sorry.