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Western Digital SN850 500 GB

500 GB
Capacity
WD 20-82-10034-A1
Controller
TLC
Flash
PCIe 4.0 x4
Interface
M.2 2280
Form Factor
Front
Package
Gaming PH
Package
PCB Front
Gaming PH
PCB Front
PCB Back
Gaming PH
PCB Back
SSD Controller
Controller
NAND Die
NAND Die
The Western Digital SN850 is a solid-state drive in the M.2 2280 form factor, launched on October 8th, 2020. It is available in capacities ranging from 500 GB to 2 TB. This page reports specifications for the 500 GB variant. With the rest of the system, the Western Digital SN850 interfaces using a PCI-Express 4.0 x4 connection. The SSD controller is the Black G2 (20-82-10034-A1) Triton MP16+ from WD, a DRAM cache chip is available. Western Digital has installed 96-layer TLC NAND flash on the SN850, the flash chips are made by Toshiba. To improve write speeds, a pseudo-SLC cache is used, so bursts of incoming writes are processed more quickly. The cache is sized at 156 GB. Thanks to support for the fast PCI-Express 4.0 interface, performance is excellent. The SN850 is rated for sequential read speeds of up to 7,000 MB/s and 4,100 MB/s write; random IOPS reach up to 800K for reads and 570K for writes.
At its launch, the SSD was priced at 149 USD. The warranty length is set to five years, which is an excellent warranty period. Western Digital guarantees an endurance rating of 300 TBW, a typical value for consumer SSDs.

Solid-State-Drive

Capacity: 500 GB
Variants: 500 GB 1 TB 2 TB
Overprovisioning: 46.3 GB / 10.0 %
Production: Active
Released: Oct 8th, 2020
Price at Launch: 149 USD
Part Number: WDS500G1X0E
Market: Consumer

Physical

Form Factor: M.2 2280 (Single-Sided)
Interface: PCIe 4.0 x4
Protocol: NVMe 1.4
Power Draw: Unknown

Controller

Manufacturer: WD
Name: Black G2 (20-82-10034-A1) Triton MP16+
Architecture: ARM 32-bit Cortex-R
Foundry: TSMC FinFET
Process: 16 nm
Flash Channels: 8 @ 1,200 MT/s
Chip Enables: 4
Controller Features: DRAM (enabled)

NAND Flash

Manufacturer: Toshiba
Name: BiCS4
Rebranded: (Rebranded by Sandisk)
Type: TLC
Technology: 96-layer
Speed: 533 MT/s .. 800 MT/s
Capacity: 2 chips @ 2 Tbit
Toggle: 3.0
Topology: Charge Trap
Process: 19 nm
Dies per Chip: 8 dies @ 256 Gbit
Planes per Die: 2
Decks per Die: 2
Word Lines: 109 per NAND String
88.1% Vertical Efficiency
Read Time (tR): 59 µs
Program Time (tProg): 625 µs
Die Read Speed: 551 MB/s
Die Write Speed: 56 MB/s
Endurance:
(up to)		 1500 P/E Cycles
(3000 in SLC Mode)
Page Size: 16 KB
Block Size: 1152 Pages
Plane Size: 1980 Blocks

DRAM Cache

Type: DDR4
Capacity: 512 MB
(1x 512 MB)
Organization: 4Gx16

Performance

Sequential Read: 7,000 MB/s
Sequential Write: 4,100 MB/s
Random Read: 800,000 IOPS
Random Write: 570,000 IOPS
Endurance: 300 TBW
Warranty: 5 Years
MTBF: 1.8 Million Hours
Drive Writes Per Day (DWPD): 0.3
SLC Write Cache: approx. 156 GB
(150 GB Dynamic
+ 6 GB Static)

Features

TRIM: Yes
SMART: Yes
Power Loss Protection: No
Encryption:
  • No
RGB Lighting: No
PS5 Compatible: Yes

Reviews

Same Drive

This section lists other SSDs in our database using the exact same hardware components

Notes

Drive:

This drive uses a hybrid pSLC Cache design, which can spans to almost a third of the drive's capacity. The nCache 4.0 is a really awesome design that has 6GB(*) as a Static pSLC Cache with almost 150 GB(*) reserved as dynamic which shrinks as the drives fills up.

(*) - Not 100% confirmed.

NAND Die:

Read latency tR: 58 µs (ABL)
Performance:
tPROG (typical) - 2100 µs (MSB)
tR (typical) - 59 µs
tPROG (ower page) ~ 200 µs
Estimated tPROG between 625 ~ 975 µs
Jun 1st, 2024 15:18 EDT change timezone

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