Some people seem to think that all Apple had to do to implement Fusion Drive in the iMac and Mac mini was to go out and buy some 128GB SSD. They then compare the cost of SSD components available on the open market with the $250/£200 that Apple charges for the Fusion Drive upgrade, and complain that Apple is ripping people off. But the Fusion Drive is quite unlike any of the other disk cache products out there, and someone had to sit down and write the OS code to support this. Some far-seeking systems-architecture-type guy had the original bright idea, then once the project was given the green light, thought had to be given as to how it would be supported, and a team of guys put onto the project to write the low-level code. I don't know how many guys were involved and how much they are paid at Apple but let's suppose they earn $80,000 pa. Once recruitment, training, technical equipment costs, office space, overheads, management and so forth are added this probably turns into $200,000 pa. How many were there, how long did it take... Might be looking at several millions of dollars. That's money that Apple needs to recoup through charging punters a premium over and above the open market cost of SSDs. And then Apple isn't a charity; the whole reason for innovation is to be able to charge more for your product because it's better than the competitors'. What's interesting is that some enterprising individuals have worked out that it's possible to create a DIY version of Fusion using externally mounted SSDs. Maybe they ought to keep schtum about this otherwise Apple might well tighten up the supporting code in future releases of the OS to only support their own implementation of the technology. Fusion Drive was the "WOW" moment for me when I watched the iMac introduction. If it wasn't for Fusion I might very well have bought a refurb iMac.