Hi, I’m Bryan from Dell’s enterprise HDD/SSD marketing. The IT world has started making big moves over from 3.5” 15K SAS over to 2.5” 10K & 15K. Times they are a changing, but we don’t need to start the swan song for 3.5” 15K just yet. 2.5” SAS has a lot going for it and I’m not trying to argue that. 2.5” 10K/15K SAS brings nearly a 2-to-1 power benefit over equivalent capacities in 3.5” 15K and also has a significant IOPS performance advantage if you can double the drive count within the same rack space.

Does this mean 3.5” 15K is dying or dead? No way, not yet. Out of the attributes of power, capacity and speed, you can basically pick any two you want within HDD’s. The only way to get all three is to go with an SSD and then we have to mention the cost aspect …but that’s another subject. We launched a 3.5” 15K SAS at 450GB today. If you want performance but also require capacity, this drive brings both. By comparison, it takes three of the highest capacity 2.5” 10K SAS HDD’s to hit the 450GB mark. Even at a 2/1 power benefit ratio, this goes out the window when you need three. If IOPS aren’t as important as MB/sec, the 3.5” 15K wins again. Rebuild times are a bigger issue with bigger drives, no doubt. But MTTF increases as the number of drives in a system are increased too, so there are always trade-offs to consider.

IMHO, 3.5” 15K is still the best option for finding the balance between performance and capacity. Put cost into the equation and 3.5” 450GB looks even better.