Slow SN750 4K Random Read/Write

Hi there,
I am getting really slow performance in 4K Random Read and Write benchmarking.
CDM Capture
I decided to reboot my computer in safe mode and the performance was nearly double. I thought it might be caused by BitDefender (antivirus). So I uninstalled that and restarted the computer to get the same low performance.

Here is my motherboard for reference:
ASRock Z390 Phantom Gaming 4 (Most recent Bios 4.4)

Also I am running a second SN750 1TB drive that gets virtually the same low performance.
Lastly, I am also running an m.2 Intel Wifi 6 AX200

So all three of my M.2 slots are filled. I currently have no SATA drives connected at all. Any help would be much appreciated. Thanks!

Just an update. I completely re-installed windows just in case there was an issue. I still have the exact same problem. I thought I might install some of the drivers that came with the motherboard, but none of them were specific to NVME. I tried them anyway, and it didn’t fix the problem. I’m surprised that nobody else has this issue?!?!

Did you ever figure this out? I’m having the exact same issue with the exact same drive. The RND4K write speed is absolutely atrocious, and I have no idea what’s causing it. There are no background processes eating up disk usage (that I can see).


I think mine is worse :slightly_frowning_face:.

When doing that last test, what is your CPU usage, and which CPU model are you using. That test is single threaded, and is prone to being influenced by single core bottlenecks.
PS, the 512GB version of the SN750 is slower than the 1TB model, though
PS, my SN750 is the 1TB model and currently had the payload size firmware bug since i am using it with a chipset connected m.2 slot.
The CPU that I am using in a Ryzen 7 5800x. and settings like PBO will influence the high IOPS single threaded operations, especially in my case where the payload bug doubles the CPU load of such operations.
Also if windows is running from the same drive, then IOPS will be lower as the OS is very frequently doing other read and write operations with the drive, for example, the event log will very frequently do lots of tiny writes, and the telemetry will also constantly log and periodically upload stuff to microsoft.
This is why typically you would need to test an SSD when it is not also the system drive.

If you must test it that way, then the only way to minimize the impact, is to do a clean boot (ensuring no 3rd party services or applications are loading at startup, and leaving windows alone for 10-15 minutes after startup for it to complete its other post bootup tasks.

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Mine is really really really terrible if you see it.