# WD SN850 4K read/writes much slower in Windows 11



## blasteris (Nov 30, 2021)

Hi,
recently bought WB SN850 2 TB SSD and decided to run a few benchmarks to see how it matches against reviewed ones. I expected a few percent difference, but some tests differ more than twice. I thought maybe my settings were wrong, or I didn't enable something in the bios, but after tinkering for a few hours I thought that I got a bad SSD and was about to return it, but decided to create a new partition and install Windows 10. And on Windows 10 all tests are as good as reviewers got (just AS SSD benchmark shows higher acc. time). Did same tests with Samsung 970 EVO 500 GB (my boot drive for Windows 11), and it seems that mostly write speeds are slower on Windows 10.
SN850 is in the top motherboard slot, running at Gen.4 x 4 and reaching max temp 63 C during testing.
After reading some threads, it seems that people only have write speed problems with Windows 11. Did anyone else encounter such an issue? Is it WD SN850 problem or just some compatibility issue?
Got latest bios, chipset drivers... don't know if other drivers matter?
My specs:
CPU: Ryzen 5900x
MB: Asus B550-E
GPU: RTX 3070
RAM: G.Skill 32 GB
SSD1: WD SN850 2TB
SSD2: Samsung 970 EVO 500 GB
HHD1: Seagate 8 TB
HHD2: Seagate 3 TB


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## Ferrum Master (Nov 30, 2021)

Old news... because it uses stock windows nvme driver.. It has less IRQ's and priority assigned to it.


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## blasteris (Nov 30, 2021)

Ferrum Master said:


> Old news... because it uses stock windows nvme driver.. It has less IRQ's and priority assigned to it.


So there's nothing to be done? Go back to Windows 10 or wait for new driver?


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## Ferrum Master (Nov 30, 2021)

blasteris said:


> So there's nothing to be done? Go back to Windows 10 or wait for new driver?



Why haven't you put their real drivers, for each drive, Samsung and WD have their own NVME drivers with some specific fixes too.


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## blasteris (Nov 30, 2021)

Ferrum Master said:


> Why haven't you put their real drivers, for each drive, Samsung and WD have their own NVME drivers with some specific fixes too.


Samsung driver didn't help, and it seems I can't find WD drivers. Have WD dashboard installed, but no dedicated drivers. Maybe I just don't know where to look.


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## Ferrum Master (Nov 30, 2021)

Look here.


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## blasteris (Dec 1, 2021)

Ferrum Master said:


> Look here.


Thanks for the link, but in WD driver pack there's no driver for SN850, so as recommended I installed Samsung's driver with certificate, but results are the same.


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## Ferrum Master (Dec 1, 2021)

In same manner update AMD drivers and adjust power plan PCIe settings.

Other than that I do not exhibit any performance degradation on my Samsung drive on Win11. Keep in mind those benchmarks are very single thread, high CPU clock dependent.


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## Solid State Brain (Dec 1, 2021)

I have Windows 11 Pro and a WD SN850 1TB on a B560 Intel platform. I think I am having similar issues, but strangely they are partition-dependent. If I create a new empty partition at the end of the drive, performance (in particular peak write performance) seems about right, but if I test it on C:, I get only about 300k IOPS peak for writes instead of about 700k.

Other performance figures are also apparently affected (and testing with a new partition appears to bring the full performance back), but random peak write performance is the simplest to test (e.g. with CrystalDiskMark).


EDIT: here is a test showing the difference between the C: and D: partitions. Similar differences also occur with larger testfiles; I chose 256 MiB just make the test less wasteful. Sometimes the D: partition too starts behaving oddly (slightly slower performance, also with reads, but this can be mainly observed with different tests), and creating a new one after shrinking it shows back the full performance of the SSD.

I'm unsure whether this is Windows' or the SSD's fault, but I do not understand why there would be any performance difference on other partitions while the OS is installed and running on the same SSD. Trim seems to be running (and was manually performed as well); data fragmentation on the benchmark testfiles does not seem to be occurring (while it won't destroy performance as with hard disks, it can affect peak performance also on SSDs).






EDIT: I've also already set the SSD to 4kB LBA (with nvme-cli from a Linux installation on a different SSD; reinstalling Windows is then required as it deletes everything and makes the drive incompatible with partition images made with 512B LBA), which improved performance marginally but did not solve this issue.

EDIT: It looks like this person on Reddit saw the same problem as I did: Windows 11 slows NVME writes greatly, on small (128GB) partitions? : Windows11 (reddit.com)


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## blasteris (Dec 1, 2021)

Ferrum Master said:


> In same manner update AMD drivers and adjust power plan PCIe settings.
> 
> Other than that I do not exhibit any performance degradation on my Samsung drive on Win11. Keep in mind those benchmarks are very single thread, high CPU clock dependent.


Changing/adjusting power plan did nothing. About which AMD drivers are you talking? Chipset drivers or some storage drivers? Because I only see some old drivers and RAID drivers.


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## Ferrum Master (Dec 1, 2021)

blasteris said:


> Changing/adjusting power plan did nothing. About which AMD drivers are you talking? Chipset drivers or some storage drivers? Because I only see some old drivers and RAID drivers.



Yes chipset one, and the latest ones, that are actually for AMD_Chipset_Drivers_3.10.22.706 by MSI.

Did a rebench. PM981 performs roughly the same for me. Rounded corners are w11.


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## Mussels (Dec 7, 2021)

I thought those were my images, as i did the same testing months ago and even used MS paint with the same bad red text
The only difference is i tested vs a 970 Pro, not a 970 evo. serious deja vu there.

Windows 11 has issues with some drives, 4K writes are really low - and it's worse on smaller partitions <200GB)

There is no fix, yet.

This is the one i had around september?


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## Solid State Brain (Dec 7, 2021)

The problem seems worse if Core Isolation/Memory Integrity is enabled. Can others confirm?
The system partition is affected the most; other partitions on the same SSD may or may not be affected.


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## Mussels (Dec 8, 2021)

I cant even load that screen (TPM/SB free install)


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## OneMoar (Dec 8, 2021)

use extreme caution when replacing the NVME Driver
I have seen many reports of unrecoverable BSODS On boot after installing a vendor specific nvme driver


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## Mussels (Dec 8, 2021)

OneMoar said:


> use extreme caution when replacing the NVME Driver
> I have seen many reports of unrecoverable BSODS On boot after installing a vendor specific nvme driver


I dont think we HAVE any third party ones for windows 11 yet


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## Ferrum Master (Dec 8, 2021)

I wonder what exactly I am disabling or enabling that I do not exhibit any of those on my drive... I got actually better more consistent performance.

I use mostly tweaks given by W1z in the w11 tweaks sections, I disable anything Defender and exploit protection related. Hyper V is disabled also.


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## Mussels (Dec 8, 2021)

I went back and found my old benchies and re-tested them, and my current Win 11 results are very close to the W10 ones now.


Same hardware, same OS - just windows updates and AMD chipset driver updates since then.

@blasteris have you installed the AMD chipset drivers for Win 11?


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## Ferrum Master (Dec 8, 2021)

Mussels said:


> @blasteris have you installed the AMD chipset drivers for Win 11?



Yea, I asked it too, as the benchies are very single thread/boost frequency touchy. As default W11 UEFI preferred cores/CPPC2 feature is non existent, AMD's do not boost to max speeds, thus the benchmarks are worse without the AMD driver and Windows patches.


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## RJARRRPCGP (Dec 8, 2021)

Ferrum Master said:


> performs roughly the same for me.
> 
> 
> View attachment 227218


Actually, it seems better with 11 this time.


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## blasteris (Dec 8, 2021)

Mussels said:


> @blasteris have you installed the AMD chipset drivers for Win 11?


Yeah, I have the latest chipset (3.10.22.706) and other drivers, latest bios. I just don't get why my Win11 results are so much worse than Win10. Others get 10-20% better performance in RND4kQ32 in Win10, while mine are more than 300% in some instances.


Solid State Brain said:


> The problem seems worse if Core Isolation/Memory Integrity is enabled. Can others confirm?


Can't test this. I assume you can toggle this only if you enable virtualization and if virtualization is turned off so is memory integrity?


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## Solid State Brain (Dec 8, 2021)

blasteris said:


> Can't test this. I assume you can toggle this only if you enable virtualization and if virtualization is turned off so is memory integrity?



Yes, the CPU's virtualization features first have to be enabled in firmware. Some drivers may also prevent you from toggling Memory Integrity.


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## blasteris (Dec 8, 2021)

So decided to create a new partition and install a fresh win11 copy. And after installing latest chipset driver and all Windows updates, all my benchmarks (except RND4K Q32T16 writes) were like win10 or better. It seems that there's something wrong with my Win11. Don't know if it's correlated or not, but I formatted test partition in 4 KB allocation unit size. Before, I always used default.


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## Solid State Brain (Dec 8, 2021)

@blasteris : does repeating the tests (mainly the RND 4K QD32T16 one from CrystalDiskMark) on your system partition (usually C: ) show the same results?

Do you also notice whether in general CPU occupation is higher during these tests on Windows 11 than on Windows 10?


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## blasteris (Dec 8, 2021)

Solid State Brain said:


> @blasteris : does repeating the tests (mainly the RND 4K QD32T16 one from CrystalDiskMark) on your system partition (usually C: ) show the same results?


Did test on both partitions and looks like they are almost the same.












Solid State Brain said:


> Do you also notice whether in general CPU occupation is higher during these tests on Windows 11 than on Windows 10?


Didn't look into it and already deleted partition with Win10.


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## OneMoar (Dec 8, 2021)

you can use this tool to completely disable virtualization based security





						Download Device Guard and Credential Guard hardware readiness tool from Official Microsoft Download Center
					






					www.microsoft.com


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## Mussels (Dec 9, 2021)

blasteris said:


> So decided to create a new partition and install a fresh win11 copy. And after installing latest chipset driver and all Windows updates, all my benchmarks (except RND4K Q32T16 writes) were like win10 or better. It seems that there's something wrong with my Win11. Don't know if it's correlated or not, but I formatted test partition in 4 KB allocation unit size. Before, I always used default.
> 
> View attachment 228112View attachment 228114View attachment 228115View attachment 228116


you arent using default settings in CDM, to start with

Default (and only supported size to boot windows) is 4K clusters

Your AS SSD results are within margin of error with mine, in W11 (Mines on the right)
(I have browsers and half a dozen programs open, so my results are normally a little higher)





I'll reboot and test in W10, but you may just have CDM not at the defaults (5 runs 1GB) and be seeing different results from that


Edit: W10 result (with nothing active on the SN850)
So... your result is faster than my W10 result? Whats the issue?


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## blasteris (Dec 9, 2021)

Mussels said:


> Edit: W10 result (with nothing active on the SN850)
> So... your result is faster than my W10 result? Whats the issue?


My issue was/is with my original Win11 copy. Fresh Win11 copy seems to be as good as Win10 except for that one CDM test. I re-ran with default settings 5x1GB and the result was just slightly better.




The same result can be repeated with Anvil's benchmark (last row). Left Win10, right Win11.






So now I know that my original problem is with my Win11 copy. Should have tried first on fresh Win11 install before posting. Just don't know what did I do to my Windows that it got so botched. Other (CPU, GPU) benchmarks run fine.


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## Mussels (Dec 9, 2021)

blasteris said:


> My issue was/is with my original Win11 copy. Fresh Win11 copy seems to be as good as Win10 except for that one CDM test. I re-ran with default settings 5x1GB and the result was just slightly better.
> View attachment 228233
> 
> The same result can be repeated with Anvil's benchmark (last row). Left Win10, right Win11.
> ...


You arent the only one to have had that issue, and you had no way of knowing the cause so dont feel bad



I think this was actually just addressed in a windows update:
It's listed in the notes for a nov 22 pre-release, but NOT in the longer version of the notes posted elsewhere online
November 22, 2021—KB5007262 (OS Build 22000.348) Preview (microsoft.com)


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## rc_ski (Dec 16, 2021)

I'm still seeing the same issue where it seems my SN850 is capped around 3.2GB on W11. I have the latest chipset, W11, WD driver, etc. I've done everything in this thread other than reinstalling W11, anyone have any other suggestions?


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## eidairaman1 (Dec 16, 2021)

Ms is to be releasing a patch for SSDs


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## INSTG8R (Dec 16, 2021)

Ferrum Master said:


> Old news... because it uses stock windows nvme driver.. It has less IRQ's and priority assigned to it.


Yeah I’ve found that the hard way with my recent purchase of a Corsair MP 600 Core 2TB Gen4…I mean I’m pretty much saturating my lanes anyway but it really doesn’t perform all that much better than my 500GB Gen3 970 Evo Plus boot drive . I mean it’s just a game drive and it’s running off the chipset so I don’t “need” blazing speed just the space…


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## rc_ski (Dec 16, 2021)

eidairaman1 said:


> Ms is to be releasing a patch for SSDs


Yeah I thought the patch above might have fixed it but doesn't seem to be the case 
November 22, 2021—KB5007262 (OS Build 22000.348) Preview (microsoft.com)


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## Mussels (Dec 16, 2021)

rc_ski said:


> I'm still seeing the same issue where it seems my SN850 is capped around 3.2GB on W11. I have the latest chipset, W11, WD driver, etc. I've done everything in this thread other than reinstalling W11, anyone have any other suggestions?
> 
> 
> 
> View attachment 229075View attachment 229076


Can you confirm what speed the NVME slot is running at with a program and show us?

You've given us no information to go by, we need your system specs


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## Solid State Brain (Dec 16, 2021)

rc_ski said:


> Yeah I thought the patch above might have fixed it but doesn't seem to be the case
> November 22, 2021—KB5007262 (OS Build 22000.348) Preview (microsoft.com)



It doesn't fix random write performance with my SN850.  Newly-created non-system partitions are still unaffected.


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## Mussels (Dec 16, 2021)

Solid State Brain said:


> It doesn't fix random write performance with my SN850.  Newly-created non-system partitions are still unaffected.


I dont know why you change everything off defaults, i cant even get mine to copy the settings you've chosen "Q32T16" doesnt show in mine

Use defaults dude, or it's useless to compare


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## Solid State Brain (Dec 16, 2021)

@Mussels
I just used "Settings > NVMe SSD" and decreased the number of test repetitions and benchmark size. The former option has a more intense random test (16 threads instead of 1); the other settings give similar results without significant differences from larger benchmark sizes, avoiding pointless writes (at this point I must have already written a few TB just by doing benchmarks).


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## Metroid (Dec 16, 2021)

Yeah, everything is messed up on windows 11 regarding ssd's and I'm not sure why.


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## Mussels (Dec 16, 2021)

Solid State Brain said:


> @Mussels
> I just used "Settings > NVMe SSD" and decreased the number of test repetitions and benchmark size. The former option has a more intense random test (16 threads instead of 1); the other settings give similar results without significant differences from larger benchmark sizes, avoiding pointless writes (at this point I must have already written a few TB just by doing benchmarks).


yeah but if you want anyone else to compare to your results, you have to state that every time you post - otherwise people are going to compare apples and oranges, and no ones going to benefit

Test repetitions, sure. but the test size? that can make a huge difference.


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## Solid State Brain (Dec 16, 2021)

Mussels said:


> yeah but if you want anyone else to compare to your results, you have to state that every time you post - otherwise people are going to compare apples and oranges, and no ones going to benefit
> 
> Test repetitions, sure. but the test size? that can make a huge difference.



I just repeated the test with 3 * 1 GiB using the "NVMe SSD" testing profile. Same differences observed. C: (system) partition has about half the random write performance compared to the other partition:






Since large differences are just observed with random write IOPS, it's faster and more convenient to perform only the random test with 1 * 128 MiB size.


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## blasteris (Dec 16, 2021)

Microsoft is planning to release update KB5007262A, which should further address NVMe problems.


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