DxO please can you fix the browser on Photolab. Looks like you might have a memory leak or something because the scrolling performance gradually degrades until it is so laggy it becomes unusable. To fix it I have to restart the application and then it works OK for a few minutes before it starts to slow down again.
The problem is PL converts the RAW images as it goes which as John-M says if there are a lot that’s the problem. Other programs ether use the jpg or create an image data base. PL is useless as a program for “viewing” folders, other use FastViewer or I use FastStone Image Viewer for initial weeding. PL really doesn’t work well with large folders. But as above you will get no response from DXO here and need to contact support
Fully agree with @duncang , it’s 2024, DxO is a program for dealing with photos, no excuses about not being able to preview them quickly, even moreso that all fancy processing and corrections can be turned off while previewing. Completely ridiculous we should need a separate program to “preview” photos.