Restoring AMD X570 Performance.
It’s all to do with the X570 chipset on certain motherboards … but hey, Western Digital has got a firmware that fixes the issue.
Taken from TPU … Western Digital is reportedly preparing a firmware update for its WD Black SN850 M.2 NVMe SSD that restores the drive’s write performance levels on PCs based on the AMD X570 platform. This problem is localized to X570, specifically to when the drive is installed on an M.2 NVMe slot that is wired to the X570 chipset. Drives that are installed on the slot that’s directly wired to the Ryzen processor perform as expected (Ryzen 3000 “Matisse” and Ryzen 5000 “Vermeer”).
The drive performs as intended on AMD B550, as well as Intel platforms that support PCIe Gen 4, as the only Gen 4-capable M.2 slots are the ones directly wired to the processor. Western Digital localized the problem to certain X570 motherboards that have their PCIe maximum payload size (MPS) value set at 128 bytes. This dictates the maximum transaction layer packet (TLP) that goes through the PCIe controller, and a low MPS value cripples performance. The firmware update by Western Digital possibly works around this limitation. The company is expected to release the firmware update by 12 July, 2021.