to speed up cops:
1 - faster computer with faster HDD for libraries
2 - newer version of PHP (7.3 should be faster than 5.5)
3 - split your big library in smaller libraries (works for me)
4 - cache the thumbnails on the server side: use setting
Code:
/*
* Directory to keep resized thumbnails: allow to resize thumbnails only on first access, then use this cache.
* $config['cops_thumbnail_handling'] must be ""
* "" : don't cache thumbnail
* "/tmp/cache/" (example) : will generate thumbnails in /tmp/cache/
* BEWARE : it has to end with a /
*/
$config['cops_thumbnail_cache_directory'] = "/path/to/cache/";
On what hardware, OS (Windows/linux) and software (webserver/php) are you running COPS?