I'm trying to decide on the right, or I guess ideal, hard drive configuration for the new iMac that I am about to purchase. I plan to install and use Lightroom on the iMac (note that I have not used Lightroom before, so I am a bit unfamiliar with the whole catalog and photo files thing being separate, but I get the concept generally). As you may know, Apple has introduced a Fusion Drive, it comes either in 1TB or 3TB. Basically, it's sort of like a hybrid drive, with a 128 SSD HD and either a 1TB or 3TB regular HD (which I believe runs at 7400 RPM). The idea is that the Fusion Drive automatically figures out which files/applications you use the most and puts those on the SSD portion for faster access, and the less often used files (old videos, pictures, documents, etc..) get put on the the non-SSD portion of the drive. Initially I was leaning toward the 3TB, but I read that as of now one can't install Bootcamp on the 3TB drive; Apple does not support it. So, even though Apple may come up with a fix, I am now thinking of the 1TB drive as I may want to use Bootcamp in the future. I guess my question is, Bootcamp issue aside, which configuration would produce the best Lightroom results/performance in your opinion: The 1TB Fusion Drive (with Lightroom and the catalog file on the Fusion Drive) and the actual image files on an external USB drive, or having everything (Lightroom, catalog file, image files, etc..) on the single 3TB drive? Do I lose any speed/performance by storing the image files on the external drive? I am new to iMacs and Lightroom, so any help advice/opinions would be much appreciated! Thanks!