I am getting settled on my new PC, and as I start to use LR, I woundered if perfomance would be influenced by where I choose to have the LR catalog.
I have several disks to choose from:
1 OS disk with Lightroom, PS and other programs
2 Disk with images to work on
3 Scratchdisk and archive of finished pictures
4 page disk and archive backup
By default the catalog is now on disk 1.
[a href=\"index.php?act=findpost&pid=187219\"][{POST_SNAPBACK}][/a]
Short answer: Unless your disk is an SSD, keep the library and images separate, and keep your library on the fastest disk.
Long answer: I've recently moved to an entirely-Mac setup and took my LR stuff to an external drive, both catalog and images. Performance was horrible - just trying to scroll down in the library view would have the mouse go into beachball mode for five to ten seconds. Fearing that I might have to invest in more hardware, the first thing I tried was to take the catalog back into the main drive - and voila, performance was great! Takes a while for the images themselves to load the first time, but browsing keywords is no longer a pain.
The reasons are, of course, contention. Both on the link to the harddisk (which for me unfortunately is USB) and on the disk in form of seek times. The catalog is most likely being accessed very randomly, so it needs a really fast disk (SSD would be best). The images are read more sequentially, so something slower can work there. Having the images and catalog on the same disk and bus virtually guarantees poorer performance.
It would appear, however, that the LR catalogs are quite resilient towards being moved, so you can try it out yourself.
-Lars