I would like some way to test pdf loading and rendering speed.
My ideal tool would let me drag and drop a batch of pdfs processed using ghostscript or sometimes k2opt, and compare some useful figure, such as the processor time or the memory usage to render the 1st page, or the 1st 10 pages, which would help me decide whether to go with k2opt instead of ghostscript. Or to try another processing option.
I am using MacOS 10.14.5 on a Mac Mini, and am using a Kindle Dx. Many newer pdfs will not load on the Kindle Dx, or will lose certain images, or will lose all page images.
I currently use a combination of ghostscript, Willus's k2opt, and ocrmypdf to pre-process pdfs for the Kindle, which also tends to speed loading on the Mac.
For pdf-born-pdfs with good text: I use ghostscript, to print to pdf, with compatibility levels 1.4. I run this in Automator and can't recall the full code with standard syntax.
For scanned pdfs with good text: I use k2opt -mode copy -dev dx. I usually run this in Automator.
For any pdfs with bad text: I either run k2opt -mode copy -dev dx or just k2opt -mode copy, and then take the result and run ocrmypdf -f --output-type pdfa-1 on it. I have not been able to run this in Automator, probably due to sandbox issues.
I previously experimented with using Ghostscript's compression settings, but these sometimes expanded pages so only the lower left corner was on-page. So I no longer use these settings.
These fixes usually solve compatibility problems and help with loading time problems, but a lot of the Ghostscript results still have excessive loading times.
I tried adding -dFastWebView but it did not help.
I often end up using k2opt, and rasterizing everything, simply to open files at a reasonable speed.