[ssokolow]

Yeah. The presence or absence of compiled extensions is a HUGE factor. Implementation design is also huge.

For example:

Geeqie is an image viewer/manager. It's a fork of the abandoned GQView and is apparently made in the image of Windows 9x-era ACDSee. It's written in C++ and uses GdkPixbuf.

My first prototype for re-creating Geeqie's collection view in PyQt so I could integrate it into a different kind of image management tool was twice as fast at loading thumbnails.

(Something on the order of 20s vs. 10s for loading somewhere around 7000 thumbnails on a 65W TDP dual-core Athlon from 2011.)

I tried quickly benchmarking GdkPixbuf, QImage, Pillow, and the Rust image crate against each other and found that, if anything, GdkPixbuf is a little faster than PyQt... but whatever Geeqie is doing cuts that performance in half.

(And that's with the Python version clamped to single-threaded image loading because I haven't yet written a smart I/O scheduler to allow parallelism on SSDs while avoiding thrashing rotating drives. Experiments with the QThreadPool-limiting line commented out show a speed-up from 10s to roughly 7s, consistent with how much of the overall system CPU capacity was taken up with other things like Firefox at the time.)