Being an industry leader requires a willingness to blaze trails in previously unexplored areas. Samsung is the world's largest NAND memory fabricator, and they have displayed a repeated willingness to lead with innovative products. The latest transition began in the client space with the 840 EVO. Samsung initially released this three-bit-per-cell (TLC) SSD last year, even though some felt trepidation at its lowered endurance.
Samsung allayed the hyperventilating enthusiasts' fears by providing a solid warranty, innovative techniques to boost performance, and a line of compelling features. A year later, the use of TLC NAND is commonplace. The 840 Evo is known for performance, reliability, and its competitive price point.
Samsung already has the PM853T 3bit MLC NAND SSD in the OEM space, and the company has expanded that out into the retail market with the 845DC EVO. Samsung has the strategic advantage of being the only SSD manufacturer with a 3bit NAND SSD on the market. While others are bringing inaugural products to market soon, Samsung is already moving ahead with expanded applications for value-oriented 3bit NAND.
Samsung is delivering the same value proposition presented to the client space into the datacenter, but with enhanced features and a longer five-year warranty. The latest enterprise SSD releases have all focused on delivering the best value for users, and Samsung plans on driving even more value into the datacenter with its 845DC EVO. This starts by utilizing 19nm Toggle 3bit MLC NAND and pairing it with a 2 million hours MTBF and an UBER rating of 1 sector per 10^17 bits read. These industry-standard reliability metrics should assuage any concerns about reliability.
The 845DC EVO features adequate endurance numbers for read-centric entry-level workloads, such as read-cache, search/indexing, and content delivery, workstation, and webserver applications. Cheap client SSDs fulfilled these entry-level datacenter workloads in the past, but the expansions of manufacturers' product stacks have provided more datacenter-friendly options.
In comparison to the other products in our test pool, the 845DC EVO has a lower endurance level of only 0.35% Drive Writes Per Day (DWPD). The 845DC EVO is purpose-built for read-centric applications, and even some of the latest cutting-edge PCIe SSDs feature only 0.3% DWPD to address similar workloads.
The 845DC EVO comes in the 2.5-inch form factor in capacities of 240GB, 480GB, and 960GB. Performance specifications are very competitive, starting with a class-leading 87,000 random read IOPS. Random write IOPS weigh in at 14,000 IOPS for the 480GB and 960GB capacity points, and the 240GB drive offers 12,000 random write IOPS. Sequential read speed is 530 MB/s for all capacity points, and the write speed is 410 MB/s for the 480GB and 960GB models, and 270 MB/s for the 240GB.
One of the primary differentiators between client and enterprise SSDs is power loss protection. Samsung brings this feature, which was noticeably absent in the SM843 but included in the SM843T, into the design of the 845DC EVO. The 845DC EVO also touts advanced signal processing for error correction and end-to-end data protection built into the datacenter-optimized firmware.
Samsung has also begun a concerted effort to offer more consistent performance. Samsung is issuing a QoS spec that guarantees completion of 99.9 percent of read operations in 0.6ms, and write operations are spec'd at 99.9 percent under 7ms. There are also guarantees that maximum read will not top 115us, and write operations will stay under 55us. These limitations on maximum I/O are important for RAID and replicated environments, and it is encouraging to see more manufacturers stepping up and offering performance guarantees.
The three-bit-per-cell generation for the datacenter begins with the 845DC EVO, so let's take a closer look at the components.