Like others, I am having a frustrating time with Lightroom editing photos from a performance standpoint.
My workflow typically has me creating a new catalog for a particular photo shoot, importing the (RAW) photos and applying a custom preset on import and then editing the photos one by one in the Develop Module.
After editing a number of photos (say, 10-25) the performance of Lightroom degrades significantly and I have to exit Lightroom and re-start it to continue editing (and continue to do so until I have completed my editing).
I have done significant research into Lightroom performance issues and have tried all of the suggestions and all possible permutations thereof to no avail. I have also profiled Lightroom with a number of Windows development tools to take a look at it's I/O, threads, memory, etc. and nothing specifically stands out.
I do understand that Lightroom stores it's editing changes (whether via a preset or manually) in a SQLite database and then applies these changes to a photo in 'real-time' to render what you see on the screen. That leads me to believe that the program is having a difficult time querying the database and applying the changes in 'real-time'... it is almost like there is a 'leak' as one moves from one photo to the next.
Edit: I took a quick look at the Lightroom .lcat file which is actually a SQLite database. In it, I found 102 tables. Still looking at the relationships between these tables.
All of the suggestions to add faster disks, larger caches, build previews, etc. are all masking the real culprit which I believe is an internal data structure, database, etc. issue. My 'evidence' for this is that exiting and re-invoking Lightroom will always provide me great performance until I reach 10-25 photos and then I have to 'rinse and repeat'.
What I would like to know from the Lightroom software development team is whether there is a way for uses to 'peek' inside the program to know what is actually going on from an operating system and computer science perspective (open files, memory allocation, threads, locks, etc.). I would assume that the Lightroom software development team knows exactly what is going on as the program is likely instrumented. Knowing what it is that is causing Lightroom to gradually degrade its performance will help users understand how our behavior might need to change when using Lightroom to improve our experience (like perhaps not/not applying presets to hundreds of photos at once rather, do so as you edit one photo at a time).
I do love Photoshop and Lightroom and recommend the products to everyone that ask me for advice but I also believe that Lightroom's performance issues are serious and need to be addressed.