Slow WD Black SN850

[FTLN]

Hi All,

Anybody know why I'm hitting a wall on x570 with my new WD Black SN850 which is supposed to be faster than Samsung's 980 Pro ?

Setup:

X570 Phantom Gaming-ITX/TB3
5950X
64Gb Corsair
RTX 3070
WD Black SN850 1Tb​

Windows 10 freshly installed, latest drivers installed, latest bios installed and latest firmware on the NVME.

I have also installed heatsink on NVME to keep it nice and cool, it tops out at around 55c under load.


PROBLEM:

It seems I'm hitting a wall on write speeds although read should also be a bit higher.

3.13 GB/s Write

5.85 GB/s Read

Kit Gurus review of the drive shows that it should be hitting close to 5 GB/s on write and 6.5 GB/s on read https://www.kitguru.net/components/ssd-drives/simon-crisp/wd-black-sn850-1tb-ssd-review/5/

I have checked my bios on all seems to be configured correctly.

Aida64 show's drive running at Gen4 speeds

I have disabled power management PCI in power profile and have also turned of window write cache buffer flushing

Here is press release regarding this new NVME on WD website: https://www.westerndigital.com/comp...g-experience-with-expanded-wd-black-portfolio

WD_BLACK SN850 NVMe SSD – Designed to feature the unprecedented performance of PCIe Gen4 technology, this future-ready product will deliver fast read/write speeds up to 7000/5300MB/s1 (1TB model). Built with the WD_BLACK G2 controller and optimized for top-tier and high-intensive gaming (not intended for NAS or server environments), the WD_BLACK SN850 NVMe SSD will help gamers achieve supreme PC performance. It reduces game load times and transfers files faster than its predecessor while using brand new cache technology3. In addition to high performance, the WD_BLACK SN850 NVMe SSD also delivers improved low queue-depth performance over its predecessor, allowing both gaming and everyday users to experience smoother loading of applications. And, for the ultimate in aesthetics and customization, there will be an optional RGB-enabled heatsink model that cuts down on thermal throttling. The WD_BLACK SN850 NVMe SSD non-heatsink version will be available in 500GB, 1TB and 2TB capacities2 starting at $149.99 (MSRP USD).

I'm at a loss as to what to do next ????

 

[tinytomlogan]

What Slot is it in? Have you tried the one closest to the CPU?

 

[FTLN]

What Slot is it in? Have you tried the one closest to the CPU?

Come on Tom, I didn't fall of the last banana boat. Of course its on the CPU lanes LOL
In fact only one slot on this MB and its connected to the CPU

 

[AlienALX]

Try Crystal.

 

[FTLN]

Try Crystal.

Crystal Ball ?

 

[looz]

Crystal Disk Mark probably.


I'd try installing latest firmware for both SSD and motherboard. But would probably be smarter to contact AsRock support. Googling revealed some issues with nVME SSDs with particular AsRock UEFI versions, but not for your particular board or nVME.

 

[FTLN]

Same in Crystal, hitting the same wall 3.13 GB/s Write &5.85 GB/s Read...

Need some low level debugging tools to see where the bottle neck is..

 

[FTLN]

For info, this issue was caused by other devices on the same PCIe bus.
PCIe bus max payload size is determined by whichever device has the lowest max payload.
For instance the PCIe bus where my SN850 NVME is running is 512byte payload capable, but my built in wifi card and thunderbolt 3 chip only have 128byte max payload size so the whole bus runs at the downgraded speed the match these two devices. The WD SN850 can only achieve max write speeds on a 256byte payload size and disabling WiFi and Thunderbolt then allows the bus to run at 256byte and this gives me full write speed performance on the SN850, cant live without thunderbolt though so I will have to live with the downgraded write performance of the SN850.

Still to be determined though is why the SN850 doesn't like the 128byte pcie bus for its writes, other Gen3 NVME drives seem to be just fine attaining their maximum write speed on a 128byte bus (Samsung, Corsair).

 

[FTLN]

Looks like Toms Hardware finally made WD talk about this issue, new firmware inbound: https://www.tomshardware.com/news/n...nce-amd-x570-chipset#xenforo-comments-3709384