At my previous job, two of the most important C files exceeded 500k - 20k lines in one, 25k lines in the other (expression parser and declaration parser, respectively).

Emacs doesn't do so well on those files either, for reasons I don't quite understand. C-Home (M-<) from the end of the file took 3+ seconds on an 3.8GHz i7 machine, yet the command those keys are bound to - beginning-of-buffer - was instantaneous, as was M-g g 1 (go to line 1).

What are you editing a 100 meg file for? Genuinely curious. I regularly work with 2GB+ files, but I don't need to edit them. I use "less". If I really needed to make a change, I'd use some combination of sed/awk most likely.

Sure, it's not unheard of, but I think for most users, for most of the time, it's not a typical thing to happen. You instead work on a tree of small files. The odd time, I need to edit a huge file like a database dump, I'll pop open vim or nano/pico, but that isn't where I spend the majority of my time developing. I think the trade-offs are worth it, and I think it's also something that can be improved in the future. I don't view it as a critical feature.

I tried opening an 98MB SQL dump the other day to restore some wiped data. Sublime choked incredibly hard where the editor was unusable and turning off syntax highlighting did nothing. I eventually just used something else. Really would have thought Sublime, being native, could handle a measly 100mb.