I'd always assumed the opposite, seeing as a browser's primary function is to parse HTML text into DOM nodes as efficiently as possible.
But on the other hand, since document.write (rightfully) gets such little usage - and has a multitude of footguns - I wouldn't be surprised if browsers used a different, slower code path when executing it; if only to prevent it from borking the parser.
But on the other hand, since document.write (rightfully) gets such little usage - and has a multitude of footguns - I wouldn't be surprised if browsers used a different, slower code path when executing it; if only to prevent it from borking the parser.