People and reviews keep saying that if you don't reach the mark of 128GB SS, then you are going to have the full SSD experience. Now, why do I get a 1/TB storage space if not to fill in with all my stuff? Is Fusion Drive smart enough? Fusion Drive has 128GB SSD, that is used to storage the OS and frequently used Apps. Let's say my Apps take 40GB, Games 60GB, and media 200GB. Most of my Media'd go to HDD, right? same goes for games I don't play for months. Now what if I don't use anything for two weeks? I'm on vacations, browsing the internet and reading my email. Would Fusion Drive empty my SSD and let everything extremely slow when I get back to work? Or it would keep my workflow on the SSD drive? What about my Aperture/Lightroom pictures? Now imagine I got my new iMac with 1TB Fusion Drive. First thing I do is installing a few apps and games, and start transfering over 500GB to my 1TB drive, and I know the first 110GB or so will be lightning fast, then HDD will take over and I'm going to wait forever, it's ok though, one time transfer. My 1TB Fusion Drive is half full. What is going to happen when I start using my iMac? Will the Fusion Drive take much to realized that I was just migrating my files to the new machine and I don't want my media files on SSD, but HDD? How fast is it going to be? I keep going from SSD to FD and back, and I just realized only a small part of 512GB SSD would be used to benefit most folks, reason why some users consider 256GB SSD. Then again, there are some information that are not clear on reviews, things only a Fusion Drive user can tell us, and I hope they do, because I am btw worldsin a place where 512GB is more expensive than 3TB Fusion Drive. I want to know better about Fusion Driver's Brain.