Slow SSD performance (Toshiba 1TB NVMe)

Question

I have a 1TB Toshiba NVMe SSD, but I have very slow write performance on this drive. I noticed that write performance in SQL Server was very poor, so I ran a test with AS SSD benchmark. The read performance is as expected for this drive, but write performance is dramatically low.

The 4K write operation took so long that I had to abort it. Do you have any recommendation? This drive was shipped with my Dell Precision 5510 and I use the Windows 10 Pro image as supplied by Dell.

Answer 1

You are likely suffering from the Force Unit Access type for your write operations. While it is meant to maintain durability for all writes, there might be regressions especially with NVMe drives and certain device / firmware / driver combinations. The PCMark FAQ is describing something very similar:

PCMark 8 Storage test score is lower than expected. I have a NVMe disk. Why?

[...]

Long answer: New NVMe storage devices run on a completely new software stack. Traditional SATA drivers are not used and instead there's a new driver in Windows that can be either implemented by the device manufacturer or it can be the standard NVMe driver provided by Microsoft. What is different from old software stack, is that there's a command called FUA (force unit access) that is now implemented in Microsoft's driver so that all write operations are enforced to be written not only on a cache but on the non-volatile media. This is different from how AHCI was implemented and will lead to reduced performance. The benefit of the implementation with Microsoft NVMe driver is that it keeps your data safe in case of power outage or system crash. The storage performance (and as a side result also PCMark 8 Storage score) may be improved by installing device drivers provided by the device manufacturer. For example, Intel provides drivers for Intel 750 SSD that improve the performance. Another option is to tweak storage device policies in Windows. Futuremark does not recommend modifying Windows cache policies on a production system since it can lead to data loss during a power failure or a system crash.

[...]

If the NVMe drive is part of your Dell order and the system is still under warranty, ultimately contact Dell support about this issue. They might be able to supply you with newer drivers and / or firmware for this drive which might resolve your problem.

Otherwise, you might want to try OCZ RevoDrive 400 drivers (The RD400 is essentially a retail version of the Toshiba XG3) instead of whatever's pre-shipped with your image. Also, enabling write caching for the drive (if disabled) might speed up matters.

Answer 2

I have updated the Intel Rapid Storage Technology drivers to 14.8.0.1042 and this increases the SSD performance quite a lot. Read performance is a little bit higher, but write performance is now on par.

Answer 3

I had this same problem on my new Dell XPS 15. Got really slow benchmark scores even with the latest RST driver. I noticed my BIOS was set to RAID mode. I suspected switching to ACHI mode would allow me to install the correct driver; however, this is not easy to do as it blue screens your install. In order to switch an already setup machine from RAID to ACHI, do this.

1. Press Shift and restart.
2. Select the option to restart in advanced mode.
3. Restart in Safe Mode.
4. As soon as you restart go into BIOS (F2 on the Dell) and change to ACHI mode.
5. Allow the boot and select Safe Mode.
6. Go to Device Manager and right click on IDE/ATAPI controllers.
7. Install the ACHI RST driver from Intel. Note it will say ACHI in the driver description instead of RAID.
8. Reboot.
9. Your computer will now have ACHI driver but the generic NVM controller under Device Manager.
10. Right click on storage controllers and install the RST driver. You will be prompted the install is not safe because Windows can't tell if it's the right hardware. Press continue.
11. Reboot and enjoy full performance.

Here are benchmark results:

This is how it should look in Device Manager: