WD Black SN770 Vs SN850X: Midrange Versus Flagship

WD Black SN850X Vs SN770The WD_Black SN770 was released in 2022 and quickly became one of the most popular M.2 SSDs among PC builders and upgraders. Although it lacks DRAM and targets the mainstream market with a reasonable price tag, it greatly impressed testers by surpassing high-end SSDs like the Samsung 980 Pro in certain real-world-oriented workloads.

Later in 2022, Western Digital added the SN850X to its lineup – an updated version of the SN850 from early 2021. This drive, on the other hand, is clearly positioned at the high-end and comes with far more impressive specs as well as onboard DRAM.

At the time of writing (2023), NAND and SSD prices have dropped further and brought the SN770 and SN850X closer together in terms of pricing. If you are undecided between the two ahead of a storage upgrade or a new build, here’s how they differ according to our data.

SN770 Vs. SN850X: Specifications

For the sake of simplicity, this table features the 2TB capacities of the SN770 and SN850X, respectively. You can view the specifications of each capacity in the respective lineups further down on this page.

WD_BLACK 2TB SN770
WD_BLACK 2TB SN850X
Western Digital WD_BLACK 2TB SN770 NVMe Internal Gaming SSD Solid State Drive - Gen4 PCIe, M.2 2280, Up to 5,150 MB/s - WDS200T3X0E
WD_BLACK 2TB SN850X NVMe Internal Gaming SSD Solid State Drive - Gen4 PCIe, M.2 2280, Up to 7,300 MB/s - WDS200T2X0E
Form Factor
M.2 2280
M.2 2280
Interface/Protocol
PCIe 4.0 x4 / NVMe 1.4
PCIe 4.0 x4 / NVMe 1.4
SSD Controller
Proprietary SanDisk
Proprietary SanDisk
DRAM
N/A
2GB DDR4-3200
NAND
112L BiCS5 TLC
112L BiCS5 TLC
Sequential Read
5,150 MB/s
7,300 MB/s
Sequential Write
4,850 MB/s
6,600 MB/s
Random Read
650K IOPS
1.2M IOPS
Random Write
800K IOPS
1.1M IOPS
Endurance Rating
1,200 TBW
1,200 TBW
Warranty
5 Years
5 Years
WD_BLACK 2TB SN770
Western Digital WD_BLACK 2TB SN770 NVMe Internal Gaming SSD Solid State Drive - Gen4 PCIe, M.2 2280, Up to 5,150 MB/s - WDS200T3X0E
Form Factor
M.2 2280
Interface/Protocol
PCIe 4.0 x4 / NVMe 1.4
SSD Controller
Proprietary SanDisk
DRAM
N/A
NAND
112L BiCS5 TLC
Sequential Read
5,150 MB/s
Sequential Write
4,850 MB/s
Random Read
650K IOPS
Random Write
800K IOPS
Endurance Rating
1,200 TBW
Warranty
5 Years
Shopping Links
WD_BLACK 2TB SN850X
WD_BLACK 2TB SN850X NVMe Internal Gaming SSD Solid State Drive - Gen4 PCIe, M.2 2280, Up to 7,300 MB/s - WDS200T2X0E
Form Factor
M.2 2280
Interface/Protocol
PCIe 4.0 x4 / NVMe 1.4
SSD Controller
Proprietary SanDisk
DRAM
2GB DDR4-3200
NAND
112L BiCS5 TLC
Sequential Read
7,300 MB/s
Sequential Write
6,600 MB/s
Random Read
1.2M IOPS
Random Write
1.1M IOPS
Endurance Rating
1,200 TBW
Warranty
5 Years
Shopping Links

Last update on 2024-07-25 / Affiliate links / Images from Amazon Product Advertising API

If you go by the specifications alone, the SN850X appears significantly faster than the SN770 in every area that directly relates to performance. The SN770 tops out at just over 5,000 MB/s in sequential transfer rates, while the SN850X practically maxes out the PCI-Express 4.0 x4 interface. A similar gap can be seen in the random read/write IOPS area.

Of course, the SN770 also has no onboard DRAM buffer but instead uses a share of the system’s RAM in the form of a so-called host memory buffer (HMB).

There are also some similarities, not least that both of these SSDs use the same NAND Flash memory chips of the high-end TLC (triple-level cell) variety. Most likely, they also share some aspects of the proprietary SSD controller. Last but not least, the endurance ratings and warranty terms are identical.

SN770 Vs. SN850X: Performance

As we’ve learned from testing SSDs through the years, spec sheets are not necessarily indicative of how a drive performs in a real-world setting. Note that our testing is done with the largest capacities of each drive, meaning the 2TB SN770 and 4TB SN850X. The performance of the 4TB SN850X is however rated as identical to the 2TB capacity.

AS SSD

SN770 Vs SN850X AS SSD chart

Sequential performance with AS SSD is typically well below the specified maximum rates. In relative terms, it is still quite on the mark, with the SN850X being about 35% faster than the SN770.

CrystalDiskMark

SN770 Vs SN850X CrystalDiskMark sequential performance chart

A similar gap can be seen in CrystalDiskMark, where sequential transfer rates tend to be closer to the “up to” numbers.

SN770 Vs SN850X CrystalDiskMark random performance chart

Random 4K Q1T1 data is better at predicting general performance in everyday tasks. Here, the difference is much smaller, and the SN850X is less than 20% ahead of its midrange sibling.

Latency/Response Time

SN770 Vs SN850X latency chart

Latency in microseconds, as measured with Anvil’s Storage Utilities, is again better with the SN850X but only by an insignificant amount in the 4K write area.

SN770 Vs. SN850X: Gaming Performance

In actual games, SSD performance usually becomes less of a factor unless DirectStorage is involved.

SN770 Vs SN850X game loading times chart

The combined loading times in the Final Fantasy 14: Shadowbringer benchmark (five levels) see the SN850X coming out ahead of the SN770 by 1,6 seconds – an 18% reduction in load times.

SN770 Vs SN850X 3DMark Storage benchmark chart

UL’s 3DMark Storage Benchmark measures the average bandwidth utilized in gaming workloads like installing, copying, loading, and recording games. It places the SN850X in the lead by about 22% over the SN770 in our runs.

Conclusion

WD Black SN850X 4TB boxWe have previously concluded that the SN770 is very fast compared to other DRAM-less SSDs – especially entry-level models like the Kingston NV2. However, there is also no question that DRAM still makes a difference to overall performance, and that the WD_Black SN850X is a substantially faster SSD.
Read more:

SN770 Lineup: Full Specifications

WD Black SN770250GB500GB1TB2TB
Form FactorM.2 2280M.2 2280M.2 2280M.2 2280
Interface / ProtocolPCIe 4.0 x4 / NVMe 1.4PCIe 4.0 x4 / NVMe 1.4PCIe 4.0 x4 / NVMe 1.4PCIe 4.0 x4 / NVMe 1.4
ControllerProprietaryProprietaryProprietaryProprietary
DRAMNoNoNoNo
Memory112-Layer TLC112-Layer TLC112-Layer TLC112-Layer TLC
Sequential Read4,000 MB/s5,000 MB/s5,150 MB/s5,150 MB/s
Sequential Write2,000 MB/s4,000 MB/s4,900 MB/s4,850 MB/s
Random Read240K IOPS460K IOPS740K IOPS650K IOPS
Random Write470K IOPS800K IOPS800K IOPS800K IOPS
Endurance200 TBW300 TBW600 TBW1,200 TBW
Warranty5-Years5-Years5-Years5-Years
MSRP $59.00 $79.00 $129.00 $269.00

SN850X Lineup: Full Specifications

WD Black SN850X
Specifications
1TB2TB4TB
Form FactorM.2 2280M.2 2280M.2 2280
Interface/
Protocol
PCIe 4.0 x4/
NVMe 1.4
PCIe 4.0 x4/
NVMe 1.4
PCIe 4.0 x4/
NVMe 1.4
ControllerProprietary
8-channel
Proprietary
8-channel
Proprietary
8-channel
DRAMLPDDR4LPDDR4LPDDR4
Memory112-layer
BiCS5 TLC
112-layer
BiCS5 TLC
112-layer
BiCS5 TLC
Sequential Read7,300 MB/s7,300 MB/s7,300 MB/s
Sequential Write6,300 MB/s6,600 MB/s6,600 MB/s
Random Read800K IOPS1.2M IOPS1.2M IOPS
Random Write1.1M IOPS1.1M IOPS1.1M IOPS
Endurance600 TBW1,200 TBW2,400 TBW
Warranty5-Year5-Year5-Year

 

Jesper Berg
Jesper Berg

I got started with PC building in the 3dfx Voodoo era somewhere back in the 1990s, and have been writing for tech publications for a bit more than a decade. In other words old enough to have lost count of the times PC gaming has been pronounced dead.

Don't hesitate to share your thoughts

Leave a reply

GPCB
Logo