Samsung SSD 845DC EVO Solid State Drive Review
Introduction and Specifications
It was about a year ago that we first took a look at the Samsung SSD 840 EVO series of solid state drives. If you recall, those drives featured a new controller and the latest generation of Samsung’s TLC NAND flash memory, which allowed the company to offer the SSD 840 EVO series at very competitive prices, despite their relatively strong performance.
Those the SSD 840 EVO series of drives was originally designed for client-PC applications, Samsung has since evolved and refined the design and deemed it suitable for read-centric enterprise applications. The Samsung SSD 845DC EVO series of drives we’ll be showing you here offer many of the same features as the 840 EVO series, but performance has been optimized for enterprise workloads and power loss protection is now built-in.
From the outside, the Samsung SSD 845DC EVO family of drives looks much Samsung’s consumer-class products. They conform to the same 2.5-inch form factor (with 7mm Z-height) as most other consumer-class solid state drives and feature a basic, brushed metal enclosure with Samsung’s logo imprinted on the top, and serial number and other identifying information on the bottom.
The 845DC EVO series enclosures are secured using a trio of pentalobe screws, which are more obscure than the typical Torx or even Hex screws used on most other drives. Should you have the necessary tools to open one of the drives up, however, you’d see that the PCBs are relatively similar to a few of Samsung’s consumer SSD, save for the additional array of capacitors that line the top and sides of the PCBs. These capacitors provide a level of power-loss protection, so the drives can complete any pending writes in the event of a power failure. Notice, since the 240GB drive has fewer components, it isn’t outfitted with as many caps.
The two drives you see pictured here are for the 240GB and 960GB versions. Both of the drives feature Samsung’s triple-core MEX controller, which operates at 400MHz. The controller is fundamentally similar to the triple-core MDX controller used in the original 840 series, though the MDX controller operated at only 300MHz. The 850DC EVO’s MEX controller has also been updated to support the SATA 3.1 spec, which incorporates a few new features, like support for queued TRIM commands, for example.
The Samsung 845DC EVO series drives also feature 1GB of DRAM cache memory and are built-around Samsung’s own 19nm Toggle 3-bit MLC NAND flash memory (a.k.a. TLC). The 240GB drive features four pieces of NAND (64GB, each), while the 960TB drive has 8 pieces (128GB, each). If you do the math, however, you’ll file that both drives leave some free NAND capacity for over-provisioning, which is typical of many current SSDs.