Loading A4 sized scanned pdf with 300dpi takes between 1 and 5 seconds per each page for iPad Retina when continuously viewing next pages, which is very slow. And it shows a blank page until it fully loads a page.

In contrast, Note-shelf shows low resolution page first then load full resolution image later. This is very convenient when searching for a specific page while scrolling to next pages. Goodreader precaches adjacent pages in advance, therefore there loading speed is very fast.

It would be nice if Goodnotes improve pdf loading speed by loading low resolution image first or precaching or improving loading algorithms.