Using multiple hardware devices in a single subsystem is a popular trend on the PC market. Enthusiasts often build graphics subsystems out of two or more graphics cards whereas users who need high computing performance can go for multiprocessor workstations. This approach works for the disk subsystem, too. It is very easy to increase its performance by combining two or more hard disks into a RAID. Data is distributed among multiple disks on level 0 RAIDs, so the resulting data-transfer speed can be increased substantially by reading from or writing to several disks in parallel.
As a matter of fact, users would often argue what RAID it would take to match the speed of an SSD when the latter was just coming to the consumer market. Of course, things are different now. The SATA 6 Gbit/s interface and the new generation of controllers have raised the performance bar of modern SSDs far above that of conventional hard disks. This gave rise to another question, though. Can we increase our disk subsystem performance by combining multiple SSDs into a RAID?
Indeed, there seem to be no reasons for RAID technology not to be beneficial for SSDs. SSDs are fast with small chunks of data whereas chipset-integrated RAID controllers offer direct communication with the CPU at data-transfer speeds which are many times that of SATA 6 Gbit/s. So, SSD-based RAID0 looks like a viable idea, especially as it doesn’t involve extra expense. The total capacity of a RAID is the sum of the capacities of its constituents whereas the price of an SSD is directly proportional to its capacity. So, if you use the free RAID controller integrated into your mainboard’s chipset, you will end up with the same cost per gigabyte of storage as with a single larger-capacity SSD.
So, SSD-based RAID0 looks attractive in theory, but we are going to check this idea out in practice. Kingston was kind to offer us two 120-gigabyte and one 240-gigabyte SSD from its top-end HyperX series so that we could directly compare a dual-SSD RAID0 with a single SSD of the same capacity.
Closer Look at Kingston HyperX SSD Series
Kingston’s HyperX series is comprised of rather ordinary enthusiast-oriented SSDs based on second-generation SandForce controllers. They employ the well-known SF-2281 chip and 25nm NAND flash memory manufactured by Intel or Micron. In other words, The HyperX series is the top-performance version of SandForce’s current platform, identical to Corsair’s Force Series GT or OCZ’s Vertex 3 in its internals.
The only thing that differentiates the HyperX series from the competitors is the eye-catching design of the case and the exclusive Toolbox utility that helps you view SSD-related information including S.M.A.R.T.
The utility resembles OCZ’s Toolbox without firmware update (Kingston offers a special tool for that) and Secure Erase functions.
As is the case with other SandForce-based SSDs, the HyperX models of 120 and 240-gigabyte capacities differ in performance. This fact is reflected in their official specs:
The difference is due to the number of NAND devices in each model. Each 25nm MLC flash die having a capacity of 8 gigabytes, the 120GB model contains 16 flash devices whereas the 240GB model, 32 flash devices. Considering that the SandForce SF-2281 controller has eight-channel architecture, the 120GB and 240GB models can use 2-way and 4-way interleaving, respectively. The higher level of interleaving means higher performance as the controller can go to another NAND device without waiting for the current one to complete its operation. This is in fact similar to RAID0 but within a single SSD, on the level of the SandForce controller.