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WD Black SN850 vs WD Black SN850X: The Practical Difference?

If you ever search for a Prosumer Gen4 NVMe SSD anywhere, you will definitely get to see WD Black SN850. We all know that it is an expensive and powerful NVMe SSD out there. It targets the premium set of users, games, and enthusiasts. It has got a lot of competitors as well.

In fact, we have done numerous comparisons of SN850 with different SSDs on SSD Sphere. But, today, we have WD’s own product ready for comparison.

Yes, we are comparing the all-new WD Black SN850X with the already-popular WD Black SN850.

You should know that the SN850X is coming with a promise of comparatively higher data read/write speed than the SN850. The 1TB variant of SN850X has 7300MB/s and 6300MB/s theoretical read/write speed.

If you compare it with the SN850’s 1TB variant, the read speed is 300 MB/s, and the write speed is 1000MB/s higher.

The SN850X is coming with the same controller but with updated firmware and components. The BiCS5 NAND Flash in SN850X is competing pretty tough with the competitors. But, the SN850 is keeping its legacy further and giving a perfect blend of affordability and performance.

We are going to test and reveal the key differences and the actual performance comparison later in the article. So, keep reading until the end.

SpecificationWD Black SN850WD Black SN850X
Storage Variants500GB, 1TB, 2TB1TB, 2TB, 4TB
Theoretical Read Speed (Seq)7000 MB/s7300 MB/s
Theoretical Write Speed (Seq)5300 MB/s6300 MB/s
Random Read Speed1,000K IOPS1,200K IOPS
Random Write Speed1,000K IOPS1,100K IOPS
Warranty5 Years5 Years
Heatsink OptionAvailableAvailable
EncryptionNot AvailableNot Available

SN850 doesn’t have a 4TB variant but SN850X comes with a 4TB variant. However, it doesn’t have a 500GB variant like the SN850.

Moreover, SN850X has a 300MB/s higher data read speed and a 1000MB/s write speed. The random read/write speed is also supposed to be higher than the SN850. But, all these things will get tested in the real-time benchmark scores. So, let’s proceed further.

Both come with the heatsink option. So, if you are going to use these SSDs for heavy tasks, you should go for the heatsink versions.

The test bench is equipped with an Intel Core i5 12600K CPU along with a 16GB DDR4 4800MHz RAM kit. The motherboard is MSI Pro Z690-A DDR5. Both the SSDs are 100% empty during the tests and 2TB variants are utilized to run the benchmark tests. Other variants may have different performance results.

For these tests, I have used the CrystalDiskMark software. CrystalDismMark is another simple-to-use storage benchmark software. It is generally used to run sequential and random system tests using different file sizes. The default sequential read/write test is 1M at Q8T1 and Q1T1. The default is random read/write test is 4KB at Q32T1 and Q1T1. You can easily change these test types along with the total test file size.

CDM Sequential results bar graph sn850 vs sn850x
CDM Sequential results bar graph sn850 vs sn850x IOPS

Do not get confused here. In this test, I have used the Game Modes of these SSDs to check the difference in benchmarks. So, there are three modes i.e. Game Mode On, Off, and Auto.

3DMark Scores Comparison Bar Graph (SN850 vs SN850X)

AS SSD is another very popular storage benchmarking software. It again runs some random tests to test sequential and random performance. You can set the test size from 1GB to 10GB. It will give you a score that can be helpful to compare the performance of two different SSDs.

We have used the 1GB Test size here for our benchmarks.

AS SSD Benchmark Scores Comparison using a bar graph (SN850 vs SN850X)

Anvils Storage Utilities is our next benchmark software with a pretty simple interface. It runs all the tests automatically and gives you a final score. A higher number means better performance. It runs a wide array of tests including Seq 4MB, 4K, 4K QD4, 4K QD16, 32K, and 128K, in both read and write formats. The test size here in this case is 8GB.

Anvil's Storage Utilities scores comparison between sn850 and sn850x

These benchmarks are done with Game Mode turned On and Off for both the SSDs. There isn’t much difference in the results. But, still, you can see that in the graph below.

PCMark 10 Storage Benchmark Scores Comparison bar graph

I am using 1920×1080 HD 1080i resolution for this test. The Test size is 1GB and the Codec is 10bit YUV.

WD Black SN850 1TBWD Black SN850X 1TB

Obviously, you have got everything by looking at the benchmark results. But, I would like to tell you that both SSDs are competing hard and creating new trends in the SSD market.

I am really impressed by the sequential and random write speed 850X is offering. But, SN850 is the winner when it comes to the read operations.

I can recommend both of these to any user who is looking just for performance. For games and enthusiasts, these are both great SSDs to go with.

ParameterWD Black SN850XWD Black SN850
2TB: 1,200 TBW
4TB: 2,400 TBW
500GB: 300 TBW
1TB: 600 TBW
2TB: 1,200 TBW
Warranty5-Years Limited Warranty5-Years Limited Warranty
MTBF (Mean Time Between Failure)1.75 Million Hours

The TBW (Total Terabytes Written) of the matching capacities is the same. However, if you go for the 4TB variant of the SN850X, it’s going to give you a huge TBW limit which means a lot of usage for a longer period of time. Overall, the WD SSDs are reliable. So, you do not have to worry about reliability and customer support.

Technical SpecificationWD Black SN850XWD Black SN850
NAND Flash TypeSandisk’s TLC NANDSandisk’s TLC 3D
NAND Flash Layers112109
ControllerWD Proprietary ControllerWD Proprietary Controller
Controller ConfigurationsTri-core/8-Channels8-Channels
Heatsink OptionAvailableAvailable
EncryptionNot AvailableNot Available
DatasheetWD Black SN850XWD Black SN850

The number of layers is definitely higher in the SN850X but it still lacks a lot. The 112-Layer BiCS5 Flash is reliable for binning but still, the opponents such as SK Hynix and Micron have some better things to offer.

The controller inside the SN850X is an updated version of the SN850 itself. SN850X again is using an 8-channel but the components including flash and firmware have been upgraded.

There were some issues reported by the users related to the SN850. One major issue was its overheating problem. The SN850X comes up with a fix to this.

Also, there was a high idle power usage which is now fixed with the SN850X. SN850X still uses a lot of power but those unwanted fluctuations are now gone.

One of the biggest advantages of the SN850X is its great post-cache performance. For gaming and content creation, this can prove to be a great benefit for users. The dedicated game mode is now improving as the company had promised after the launch of SN850X. However, the SN850 is also known for its fast-recovering SLC caching.

So, overall SN850X is a perfect pick for gaming builds as well as the PS5 users. However, the SN850 can give you a perfect balance of price and performance.

By the time I am writing this article, SN850X is surprisingly cheaper than the SN850 and I hope it remains the same. Between these both, I would recommend going for the SN850X because it has better performance. However, as we discussed earlier, the SN850 is good in terms of write operations.

Both are using the same TLC NAND Flash from Sandisk. But, both lack data encryption as well.

Overall, the SN850X is capable of providing you with better results. Now, if you are able to get the SN850 at a cheaper price or if you just want to go for it, there is no problem with it as well.

Let me know what you think about this article in the comments.

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1 year ago