Hard drives, and SA-SCSI drives especially, face growing competition from a new breed of storage device: the solid-state drive (SSD).
An SSD stores data in solid-state memory — that is, SRAM chips — rather than on conventional hard disk platters. Today's SSDs are large enough to be useful, and although not exactly economical, have come down enough in price that they can enter the conversation when it comes to outfitting a new workstation.
The advantage of SSDs? There are several, including less noise and better reliability in the face of environmental issues like vibration. Unlike the HDD, the SSD has no moving parts. But the real motivation to choose SSD is performance. More specifically, it's about much lower latency, the time that lapses between asking the drive for data and receiving it. The SSD doesn't necessarily offer a big benefit over hard drives in bandwidth — how quickly the data comes once it starts coming — but it eliminates the seek time for the hard drive's head, delivering an indisputable advantage in access time. The downside is a glaring one: price.
Given the pluses and minuses, CAD users who have a slightly higher but not unlimited budget can entertain the option of SSDs in one of two ways. A combination of HDDs and SSDs in multiple drive bays — in particular, a smaller SSD with your OS installed paired with a large conventional disk drive for data — is very practical. Or choose a hybrid drive that combines the best of both worlds. This emerging technology is effectively a two-tiered memory device that implements its bulk storage on the cost-effective hard disk while implementing a much smaller, but much lower-latency cache on SSD. For frequently accessing reasonably sized chunks of data, you get the speed benefit of SSD without breaking the bank. Whereas an SSD currently commands ten times the price (or more) per gigabyte of a conventional 7,200-RPM HDD, the hybrid drive is a relative bargain at approximately twice the price (although the premium and the performance boost will vary by model).
The bottom line on selecting storage: Buy a lot more than you think you need, especially if you've chosen a system that limits you to one or two drive bays.