In general, no... but also maybe yes. It's usually fine, but you may get extra unlucky in specific situations with specific major modes.
I've always found line length the biggest problem. Emacs has never done a fantastic job of handling long lines. If truncated, you can't see most of the content; if not truncated, the performance gets worse with length, and visual-line-mode (essential for dealing with non-truncated long lines IMO) doesn't make it any better.
Performance with large numbers of mostly shortish lines is ok. I've had no serious problems loading 2+ GByte log files (average line length <200 chars) in literal mode. The general performance suggests that Emacs isn't really tuned for editing enormous files, but I've never found things so bad as to be worth switching text editor over.
I've always found line length the biggest problem. Emacs has never done a fantastic job of handling long lines. If truncated, you can't see most of the content; if not truncated, the performance gets worse with length, and visual-line-mode (essential for dealing with non-truncated long lines IMO) doesn't make it any better.
Performance with large numbers of mostly shortish lines is ok. I've had no serious problems loading 2+ GByte log files (average line length <200 chars) in literal mode. The general performance suggests that Emacs isn't really tuned for editing enormous files, but I've never found things so bad as to be worth switching text editor over.