Date: Monday , March 18, 2013
The SuperSSpeed S301 Hyper Gold SLC Series SSD marks the entrance of an SLC NAND solution into the consumer market. SLC provides tremendous endurance and excellent performance, but the high price of this type of SSD has historically kept it exclusively in the enterprise domain.
At the other end of the spectrum, TLC has brought an increased focus on the endurance and longevity of NAND. TLC's entry into the market brings the endurance subject to the forefront, but today we have an SSD that is never going to have any serious endurance concerns in a prosumer or consumer application.
Base NAND endurance is calculated as a P/E (Program/Erase) ratio that reflects the expected number of times that each cell can be programmed and erased before it begins to produce too many data errors for the internal mechanisms of the SSD to correct.
SLC offers up 100,000 P/E Cycles, eMLC provides 15,000, MLC rates at 3,000-5,000 P/E cycles, and TLC comes in with roughly 1,000 P/E Cycles (there is no official rating). It is easy to see why SLC would be a great choice for those looking for a SSD that can handle heavy workloads. There is a huge gulf between SLC and eMLC, which is usually only seen in enterprise SSDs. That gap in endurance only widens once we get down to consumer MLC and TLC products.
Endurance isn't the only redeeming quality of SLC NAND, it also supplies superb write latency. SLC also performs well in high heat environments, which is well suited to embedded and industrial applications.
The main deterrent to purchasing SLC drives is the high pricing, but many times it is the type of SSD that SLC is integrated into that brings about the huge price tag. With the primary usage for SLC being in enterprise applications there are typically other embedded features that drive the price of enterprise SSDs through the roof. The high cost of SLC SSDs is not entirely the result of the pricing of the NAND itself.
For instance, power fail protection is a staple in an Enterprise SLC SSDs, but also adds significant costs to the SSD. Enterprise SSDs also tend to come with SAS instead of SATA, which requires specialized firmware, often with end-to-end data protection. This requires extensive development from the manufacturer. Enterprise SSDs are also infused with extra overprovisioning to provide consistent performance in demanding workloads. This can add an extra 50%, or more, of SLC NAND into the build without any additional user addressable space. This drives the cost per GB of SLC SSDs even higher.
These other features help to inflate the price of the SSD, placing SLC SSDs out of the range of consumer applications. SuperSSpeed reduces the impact of the exorbitant pricing of SLC NAND by stripping many of the features that aren't needed in an enthusiast or prosumer environment.
Removing these features and pairing the Intel 25nm SLC NAND with the reliable SF-2281 controller helps to reduce the amount of pricing overhead for the SSD. LSI SandForce provides manufacturers with reference firmware's that require little development, and a few key easily adjustable variables allow the SSD to be tweaked for the desired usage pattern.
The SandForce controller also brings the performance piece of the puzzle into play. The SuperSSpeed S301 features 550 MB/s of sequential read and 520MB/s of sequential write speed. The random read IOPS weigh in at 80,000 IOPS and the random write speed is 68,000 IOPS.
One of the key complaints from those considering SandForce SSDs is the variable performance that scales with the compressibility of the data employed. Typically there is a huge delta between incompressible and compressible data performance with LSI SandForce-powered SSDs, but the SLC NAND provides a tremendous benefit with incompressible data performance. SLC's excellent write latency reduces the penalties associated with incompressible data, resulting in a well-balanced SSD.
Today we will look at the SuperSSpeed S301 TLC SSD against several competitors of similar capacity to see if SLC makes sense in your desktop.