13.3 seconds on my desktop AMD Ryzen 7 7800X3D in KOReader fwiw. A pleasing difference. But as previously stated, my old laptop is already much, much faster than a Kobo Libra something or other. To make up for it the battery lasts only 4-8 hours instead of weeks.

(I put in a new battery earlier this year; it'd gone down to less than 2.)
Code:
09/07/25-21:22:18 DEBUG CreDocument: loading document...
[…]
09/07/25-21:22:31 DEBUG CreDocument: loading done.
09/07/25-21:22:31 DEBUG loading took 13.305 seconds
Perhaps I should add that both of those tests were with debug builds. Release builds would be a fair bit faster.