WD Black SN850 Vs SN770: Does DRAM Still Matter?

SN850 and SN770Western Digital caters to gamers and enthusiasts with its WD Black lineup. However, there are not only multiple generations of these M.2 NVMe SSDs now but also multiple tiers – let’s call them high-end and midrange.

The WD Black SN850 is a high-end PCI-Express 4.0 (Gen4) SSD that was class-leading at the time of launch (February 2021). Although it has now been superseded by the updated SN850X (see our comparison of these two SSDs here), it is still among the fastest of its kind.

WD’s SN770, on the other hand, arrived one year later and did not aim for the top of the performance charts. It instead occupies a more affordable midrange tier among other SSDs with no onboard DRAM buffer. Can it still challenge the SN850?

SN850 Vs. SN770: Specifications

To keep things reasonably simple, this table compares the 2TB capacities of the SN770 and SN850. Scroll to the bottom of this page for full specifications of the entire lineups.

WD_BLACK 2TB SN770
WD_BLACK 2TB SN850
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
Western Digital WD 2TB WD_Black SN850 NVMe PCIe 4.0 M.2 Internal Gaming SSD Without Heatsink
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 WD/SanDisk
Proprietary WD/SanDisk
DRAM
N/A
2GB DDR4
NAND
112L BiCS5 TLC
96L BiCS4 TLC
Sequential Read
5,150 MB/s
7,000 MB/s
Sequential Write
4,850 MB/s
5,100 MB/s
Random Read
650K IOPS
1M IOPS
Random Write
800K IOPS
710K 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 WD/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 SN850
Western Digital WD 2TB WD_Black SN850 NVMe PCIe 4.0 M.2 Internal Gaming SSD Without Heatsink
Form Factor
M.2 2280
Interface/Protocol
PCIe 4.0 x4 / NVMe 1.4
SSD Controller
Proprietary WD/SanDisk
DRAM
2GB DDR4
NAND
96L BiCS4 TLC
Sequential Read
7,000 MB/s
Sequential Write
5,100 MB/s
Random Read
1M IOPS
Random Write
710K 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

Even if the WD Black SN770 was launched a year later than the SN850, the latter is Western Digital’s flagship-level M.2 SSD from the previous generation. It uses onboard DRAM to speed up transfer rates and its maximum sequential performance approaches the upper boundaries of the PCIe Gen4 x4 interface bandwidth.

That being said, the SN770 is very fast for a DRAM-less SSD and also comes with a newer generation of NAND flash memory chips. It is also important to note that maximum sequential transfer rates are not the only factor that affects real-world performance. In fact, it is decidedly less important than random performance and latency in everyday workloads.

SN850 Vs. SN770: Synthetic Performance

Note that our testing was conducted using the 1TB version of the WD Black SN850 and the 2TB model of the SN770. This is a slight advantage for the SN850, as the 2TB SN770 is rated as being marginally slower than the 1TB capacity.

AS SSD

SN770 Vs SN850 AS SSD chart

In AS SSD – a popular benchmark that uses incompressible data – the SN850 offers about 23% better sequential read performance and 36% better write performance, respectively, than the WD Black SN770.

CrystalDiskMark

SN770 Vs SN850 CrystalDiskMark sequential performance chart

The SN850 and SN770 are quite evenly matched when measuring sequential write performance with CrystalDiskMark, but the SN850 pulls ahead by almost 30% in the corresponding read benchmark.

SN770 Vs SN850 CrystalDiskMark random performance chart

Interestingly, the tables are turned in favor of the DRAM-less SN770 with 4K random data at the important Q1T1 (minimum) queue depth. It’s a small but noteworthy difference of about 9%.

Latency/Response Time

SN770 Vs SN850 latency chart

Latency (measured with Anvil’s Storage Utilities) as measured in microseconds is also similar with the two drives, although the WD Black SN850 is measurably faster in the read area.

SN850 Vs. SN770: Gaming Performance

Gaming tests are always interesting – and even more so with hardware that explicitly targets gamers.

SN770 Vs SN850 game loading times chart

The 1TB WD_Black SN850 remains the fastest SSD we’ve ever tested in the FF XIV: Shadowbringer standalone benchmark. It even beats the SN850X and Samsung 990 Pro by a hair. It’s also 21% faster than the 2TB SN770.

SN770 Vs SN850 3DMark Storage Benchmark chart

The 3DMark Storage benchmark result is more in line with what we would expect, with the SN850 being less than 10% faster than the SN770.

SN770 Vs SN850 PlayStation 5 Read Speed chart

Although it is below Sony’s recommended minimum specs for slotting into the PS5, the SN770 will still work, but equipping it with a 3rd-party heatsink is likely a good idea. The SN850 is nevertheless better suited for the PlayStation 5 and is also available with an optional pre-attached heatsink.

Conclusion

In the second half of 2023, the SN850 is becoming increasingly hard to find as it has been sold out to make way for the SN850X. The newer model is a bit faster overall, but not by noticeable amounts. Both of them are however faster than the WD Black SN770, which in turn is much faster than the SN550 and other Gen3 drives.

Read more:

SN770 Series: 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

SN850 Series: Full Specifications

WD Black SN850500GB1TB2TB
Form FactorM.2 2280M.2 2280M.2 2280
Interface / ProtocolPCIe 4.0 x4 / NVMe 1.4PCIe 4.0 x4 / NVMe 1.4PCIe 4.0 x4 / NVMe 1.4
ControllerProprietaryProprietaryProprietary
DRAM512 MB DDR41 GB DDR42 GB DDR4
Memory96-Layer TLC96-Layer TLC96-Layer TLC
Sequential Read7,000 MB/s7,000 MB/s7,000 MB/s
Sequential Write4,100 MB/s5,300 MB/s5,100 MB/s
Random Read800K IOPS1M IOPS1M IOPS
Random Write570K IOPS720K IOPS710K IOPS
Endurance300 TBW600 TBW1,200 TBW
Warranty5 Years5 Years5 Years
MSRP$149.00 $230.00 $450.00
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