Western Digital has announced good news for some Black SN850 SSD owners, especially those who have installed the drive on motherboards with AMD's X570 chipset for Ryzen. The company has discovered a problem that is causing write speeds to plummet in some setups, and will be providing a firmware fix within the next few weeks.

We have not experienced this issue ourselves, and based on our own testing, the Black SN850 is one of the best SSDs for gaming.The Black SN850 is a second-generation PCI Express 4.0 model that offers faster speeds than the first round of PCIe 4.0 drives It is part of the In this case, the Black SN850 is rated for sequential read performance of up to 7,000 MB/s and sequential write performance of up to 5,300 MB/s.

In our tests, this drive was close to this nominal speed. Recently, however, we have begun to receive reports of reduced performance on some X570 motherboards. This occurs when an SSD is connected to an M.2 slot connected to the chipset.

The performance drop is no small thing; ComputerBase staff ran several tests and found that write performance was cut nearly in half when the drives were connected to the aforementioned slots. In one benchmark, write speed dropped 43.4%, from 5,255 MB/sec to 2,972 MB/sec.

Performance does not appear to be affected when the drive is installed in an M.2 slot, which is controlled by the CPU rather than the chipset. For this reason, Western Digital recommends using one of these slots while investigating a fix.

In a statement provided to our friends at Tom's Hardware, Western Digital said it plans to roll out the firmware fix next month. [WD Black SN850 NVMe SSDs may experience poor write performance when connected to chipset M.2 slots on certain motherboards, especially when the maximum payload size (MPS) is set to 128 bytes (128B). To resolve this issue, Western Digital plans to release a firmware update by July 12, 2021 that will remove this restriction on our products for this MPS setting," said Western Digital.

What if the optimal M.2 slot is already in use? The SAT is already in use, which is more than five times the maximum performance hit observed by ComputerBase.

Regardless of the SATA comparison, it is still disappointing that the performance is so far below what we paid for. Fortunately, the fix is coming in a few weeks. When the fix arrives, simply launch Western Digital's Dashboard utility, which will automatically prompt you to download and install the new firmware. Be sure to back up all important data just in case.