Tim Starling wrote:
For whole pages, generating a diff takes about 2ms plus 40ms to load the text to diff against, rendering a page takes about 800ms.
I'd gotten the impression that rendering was slower. Thanks for confirming.
So it's cheaper to use "show changes" by a factor of 20.
That much!
In fact, we've been considering suppressing the "current version" display from diff pages...
But until you do, I guess the point (i.e. which button a conscientious bot or user should press first) is moot, since the slow preview button takes 800 ms, and the fast diff button takes 40+800ms.