Now Reading
Review: Samsung 845DC EVO 240GB, 960GB SATA SSD

Review: Samsung 845DC EVO 240GB, 960GB SATA SSD

Sam ChenFebruary 13, 2015

TLC for the Datacenter

samsung-845dc-evo-ssd-custom-pc-review-5A little less than two years ago, Samsung surprised the storage industry by unveiling the world’s first 3-bit MLC, or TLC (Triple Level Cell), NAND based SSD, the Samsung 840. At the time, TLC NAND had already been in use for storage applications such as flash drives and embedded systems, but nobody really thought TLC was viable for SSDs due to TLC’s inherently higher latency and its lower endurance compared to older MLC and SLC technologies.

Despite this, Samsung is now standing behind two generations of TLC based SSDs, proving a number of our initial preconceptions of TLC incorrect – the biggest of which is drive endurance. Unlike cMLC (consumer MLC) which is generally rated at ~3,000 P/E (Program/Erase) cycles, TLC is rated at an estimated ~1,000 – 1,500 P/E cycles (the actual number hasn’t really been revealed by Samsung). While it’s easy to base assumptions of an SSD’s endurance on the NAND’s P/E cycles, this is actually a very bad measure of a SSD’s total endurance. Endurance also depends on a SSD controller’s write algorithms, write amplification, garbage collection routines, and over-provisioning which is why Samsung is capable of claiming that their TLC based 840 SSDs can do 10GB/day and has “…no workload restrictions…” on their 3 year warranty as well.

Now that Samsung has proven TLC NAND on the client side, Samsung is now the first SSD manufacturer to take the same technology to the enterprise with a datacenter oriented derivative of their Samsung 840 EVO they’d creatively like to call the Samsung 845DC EVO.

Samsung 845DC EVO Specifications

Model845DC EVO845DC EVO845DC EVO
Form Factor2.5″ 7mm SATA2.5″ 7mm SATA2.5″ 7mm SATA
Capacity240 GB480 GB960 GB
ControllerSamsung MEXSamsung MEXSamsung MEX
NAND19nm Toggle Mode 3-bit MLC NAND19nm Toggle Mode 3-bit MLC NAND19nm Toggle Mode 3-bit MLC NAND
Sequential Reads530 MB/s530 MB/s530 MB/s
Sequential Writes270 MB/s410 MB/s410 MB/s
4K Random Read87,000 IOPS87,000 IOPS87,000 IOPS
4K Random Write12,000 IOPS14,000 IOPS14,000 IOPS
InterfaceSATA 6GB/sSATA 6GB/sSATA 6GB/s
Warranty5 Years, 150 TBW5 Years, 300 TBW5 Years, 600 TBW

The Samsung 845DC EVO will come in three capacities – 240GB, 480GB, and 960GB with all three drives available in the 2.5″ 7mm form factor. Similar to Samsung’s consumer grade 840 and 840 EVO, the Samsung 845DC EVO will receive overprovisioning out of the box to help improve both drive endurance and drive performance. Like many drives on the market, the Samsung 845DC EVO will receive ~7% overprovisioning, which is ~3-4% more overprovisioning than its consumer oriented cousins.

As it’s an enterprise grade drive, the Samsung 845DC EVO will receive a 5 year, variable TBW (Total Bytes Written) warranty based on capacity. The 240GB Samsung 845DC EVO is rated at 150 TBW while the 480GB version is rated at 300 TBW and the 600GB version is rated at 600 TBW.

Probably the biggest feature that separates the Samsung 845DC EVO from its consumer oriented cousins is that the 845DC EVO will also receive full data path power loss protection. This will allow the drive to flush the contents of its DRAM cache and any data in flight into non-volatile NAND in the event of sudden power loss to ensure 100% data integrity. This is a feature that’s required for many enterprise server deployments.

Let’s take a closer look at the Samsung 845DC EVO.

About The Author
Sam Chen
Hardware and Technology Enthusiast. SSD Evangelist. Editor-in-Chief. You can find Sam's full biography here