AnandTech's Journal

Western Digital Introduces WD Red SN700: PCIe 3.0 M.2 NVMe SSDs for NAS Systems

Western Digital's Red series of drives for network-attached storage systems has a significant share in various NAS market segments. The series started off with a focus on hard drives, and more recently WD Red SSDs were introduced in Q4 2019, a few years after the SanDisk acquisition. These SATA SSDs (in both 2.5" and M.2 form-factors) were based on Marvell 88SS1074 controllers and targeted caching applications.

The increasing popularity of tiered storage, coupled with the deployment of NVMe (in the form of add-in cards, and now, natively in NAS boards) has prompted Western Digital to create a new member in the WD Red family. The new WD Red SN700 comes in 5 capacities ranging from 250GB to 4TB.

WD Red SN700 NVMe SSDs for NAS
Capacity		250 GB	500 GB	1 TB	2 TB	4 GB
Model Number		WDS250G1R0C	WDS500G1R0C	WDS100T1R0C	WDS200T1R0C	WDS400T1R0C
Controller		SanDisk In-House?
NAND Flash		3D TLC NAND
Form-Factor Interface		M.2-2280, PCIe 3.0 x4, NVMe 1.3
		Single-Sided (22.15mm x 80.15mm x 2.38mm)				Double-Sided (22.15mm x 80.15mm x 3.58mm)
Seq. Read Max (128KB @ QD32)		3100 MBps	3430 MBps		3400 MBps
Seq. Write Max (128KB @ QD32)		1600 MBps	2600 MBps	3000 MBps	2900 MBps	3100 MBps
Rand. Read IOPS (4KB @ QD32)		220K	420K	515K	480K	550K
Rand. Write IOPS (4KB @ QD32)		180K	380K	560K	540K	520K
SLC Caching		Yes
DRAM Buffer		?	?	?	?	?
Opal Encryption		?
Power	Peak	9.24 W
	PS3 (LP)	70 mW		100 mW
	PS4 (Sleep)	3.5 mW			5 mW
Warranty		5 years
MTBF		1.75 million hours
TBW		500	1000	2000	2500	5100
DWPD		1			0.7
Addl. Info.		Link
MSRP		?	?	?	?	?

A PCIe 3.0 x4 NVMe drive can provide a quantum leap in I/O performance, especially over pure HDD-based systems. NAS units are fast becoming hyperconverged application servers, and NVMe drives can improve user experience with both storage tasks as well as application tasks. In particular, tasks related to workloads like virtualization, multi-user collaborative editing and other similar applications. The benefits for traditional enterprise workloads such as intensive databases are also evident, even when the NVMe drive is used purely as a caching drive. Interestingly, the 1TB and lower capacity models have a 1 DWPD rating, while the 2TB and 4TB ones have a 0.7 DWPD endurance number.

It must be noted that Seagate has already released two generations of NVMe drives for the NAS market in their IronWolf series. WD is playing a bit of a catch-up in this particular market segment, but its SanDisk heritage and vertical integration can possibly give the WD Red SN700 an edge over the IronWolf series.