Okay I've been going thru and trying to figure out best case solution for my iMac 5K which can match my need. I got my iMac yesterday. Used migration tool to migrate applications and data I need from my Mac Mini Timemachine to my new iMac. Out of 1 TB SSD it shows nearly 560 GB is full right now. So far things looks good. Now bigger questions for storage. What is best option to follow considering I get 2 bay Thunderbolt 2 external enclosure ? Fusion of external drives (1 TB SSD + 6TB 7200 RPM HDD) HyperDuo of external drives (1TB SSD + 6TB 7200 RPM HDD) RAID 0 solution (1TB SSD + 6TB 7200 RPM HDD). I'm not sure what is difference between HyperDuo and Fusion on OS X. For Hyper Duo I am looking at this particular enclosure from DataTale RS-M2T SMART http://www.newegg.com/Product/Product.aspx?Item=9SIA54G2GR8529&ignorebbr=1 Anyone with technical information on pros and cons of each solution ?