I am considering ordering my iMac with 2TB or 3TB Fusion Drive. I normally use my computer for two main tasks: 1. processing RAW files from DSLR in Adobe Lightroom. My library has over 300 GB in total and growing as I import gigabytes of pictures every month, processing them cataloguing, retouching, exporting to JPEG and archiving for occasional future use. I would actually prefer if these RAWs go to HDD portion of the Fusion once processed. On the other hand I want my Lighroom catalog (metadata), previews and ACR cache to stay on SSD so that I can quickly browse my files search them, etc. Is the fusion drive smart enough to do that? 2. Software development. I am checking out projects using git (often up to few gigabytes of small files), indexing them, searching through them, compiling in Xcode. In total I have about 20GB of source files. I would prefer if these stay of the SSD all the times. I certainly don't want to find out that my sources were demoted to HDD after I import a few gigs of files from my DSLR... And now my question: Given by my specific use case. Do you think that the Fusion drive the right choice for me? I certainly have more than 128GB of data. On the other hand I am fine with having most of my files on the HDD supposing that my critical files are on SSD. My other alternative would be 512GB SSD, but it is pricey and given by the speed how I keep adding images I am afraid it will be small soon. 1TB SSD is quite expensive. I would like to avoid external enclosures, drives, etc. Is there any perceivable latency when using Fusion drive? I mean like opening finder window when some files are on SSD, waking-up from sleep, etc. Does Power Nap feature work on Fusion drive? Apple docs is not clear about this.