New Performance and Endurance Metrics Proposed
Since hard drive performance is measured in RPMs (revolutions per minute), SSDs need a simple performance metric for comparisons, he said. virtual RPM (vRPM) accurately and easily allows consumers to compare SSDs to HDDs and to each other when used in PCs, said Heye. "vRPM answers the question: How fast would you have to spin a virtual HDD to achieve the level of performance seen by an SSD in a client PC?" Heye predicted that SSD net performance next year will be four times faster than the current generation of SSDs and nearly six times that of the latest 2.5-inch HDDs.
Commenting on vRPM, Joseph Unsworth, research director at Gartner, said: "There has been a deluge of SSD products with varying levels of quality that have created undeserved hype and confusion for consumers and corporations. Industry support behind a common metric that clearly articulates the value proposition of an SSD on a like for like basis to a HDD will be instrumental in driving end-user understanding and subsequent adoption as prices continue to fall."
Apart from vRPM, SanDisk is proposing Long-Term Data Endurance (LDE), which simplifies endurance as a useful number, as the first industry metric of long-term data endurance. "This is a lot like measuring tread wear on a tire," said Heye. Major PC OEMs and SSD competitors have reviewed and commented on SanDisk's initial proposal, he added, and SanDisk has submitted a proposal and white paper to JEDEC, the leading developer of standards for the solid-state industry.
LDE represents the total amount of data writes allowed in the lifespan of an SSD. SanDisk will spec LDE on its future PC SSD products and "we strongly encourage others to follow SanDisk's lead," he added.
Regarding LDE's impact on SSD adoption, Greg Wong of Forward Insights said: "LDE allows OEMs a simple way to compare SSDs and determine, based on the applications usage patterns, which drives are suitable for a particular application. The beauty of LDE," he added, "is that it captures endurance in one single, understandable figure. A common metric is necessary to facilitate SSD adoption moving forward."
(Note: The LDE proposal and white paper, along with a backgrounder on vRPM, is available on the SanDisk website at www.sandisk.com/SSD/Tech_and_metrics).
