emacs -q or -Q is often quite fast. It's things like syntax highlighting, word wrapping, etc. which modes add which usually slow it down. Anything trying to run regexes over the buffer isn't going to scale well.
I think long lines are (were? [1] seems to be a new feature) a well known problem in emacs even without a custom config. There have been ways to work around this for awhile I think, but as far as I know emacs -Q isn't one of them.
oh that's neat, i didn't know about that! could help.
my ideal editor would never block, and use file-sized based approximations to allow scrolling to arbitrary locations w/o having to actually read the contents of the entire. things like syntax highlighting &c would be either strictly time-limited to not drop frames, or done in the background.
