This is a problem that I've had for ages, too. My system is absolutely not a potato (see specs below). The first time I open a book with the Calibre viewer after restarting my system (and possibly sometimes after restarting Calibre, but I'm less sure of that) it takes
forever. Every subsequent book is fine.
Today I ran the debug when opening a 539KB epub after reboot:
DEBUG: 0.0 GetFileName::__init__.py - loading translations
Initialized urlfixer
QPA platform: windows
devicePixelRatio: 1.25
logicalDpi: 96.0 x 96.0
physicalDpi: 74.88368522072936 x 74.89965870307167
ApplicationPaletteChange event ignored
Using calibre Qt style: True
ApplicationPaletteChange event received
Sandboxing disabled by user.
[0.000] Load of book started
[0.016] preparation started
[0.313] bridge ready
[0.422] iframe ready
[308.203] prepared emitted
[308.234] webview loading requested
[308.391] loading finished
I'm running Calibre 8.2.1 from the same SSD as my OS (Win10Pro, v 22H2), but my libraries are on an internal HDD.
System Specs:
32GB RAM
3.70 GHz AMD Ryzen 9 5900X 12-Core processor
nVidia GeForce RTX 3070 Ti with 8GB onboard memory and up-to-date drivers
I'd actually switched to SumatraPDF because of this, but it doesn't always display epubs properly and doesn't allow me to have persistent highlights, etc., so I'd kind of like to go back of the built-in Calibre viewer, if I can get it to stop taking 5 minutes to load a book every time I reboot my system.
