Users of Western Digital’s SN770 and SN580 SSDs are currently navigating a wave of frustrations following the recent 24H2 Windows update. Reports of crashes and the notorious Blue Screens of Death (BSODs) have emerged, particularly among those utilizing these specific models. The root of the issue appears to be linked to the Host Memory Buffer (HMB), a critical component in the performance of these DRAM-less SSDs.
Understanding the HMB Dilemma
In essence, all SSDs maintain a map of data locations within their flash memory, which is continuously updated as files are added or removed. For SSDs like the SN770 and SN580, which are designed to be cost-effective by omitting dedicated DRAM, this mapping is stored in a portion of the system’s memory, referred to as the HMB. Users have reported that while these drives typically operate with a maximum HMB size of 64 MB, the recent Windows update attempts to increase this limit to 200 MB. Unfortunately, this adjustment has proven incompatible with the firmware of these SSDs, leading to a cascade of errors.
Feedback from users on Western Digital’s community forums has highlighted various approaches to mitigate the issue. One suggested workaround involves modifying the Windows registry. By navigating to ComputerHKEYLOCALMACHINESYSTEMCurrentControlSetControlStorPort, users can locate the HMBAllocationPolicy entry. Setting this value to zero and rebooting the system disables the HMB, reportedly resolving the crashing problem for many. Alternatively, some users have found success by setting the value to 2 instead.
For those who prefer a less technical route, rolling back to the previous 23H2 version of Windows has also been a viable option. However, the ultimate solution lies in the hands of Microsoft and Western Digital, who will need to collaborate on a firmware update to address the underlying compatibility issues.
Interestingly, while numerous other SSD models operate with a 64 MB HMB, they have not faced similar complaints following the 24H2 update. This raises questions about whether Microsoft adequately communicated the changes in HMB size to all SSD manufacturers prior to the update’s rollout.
As the 24H2 update continues to be gradually released, users of the WD SN770 and SN580 SSDs are advised to exercise caution. Waiting for a firmware fix from Western Digital may be the most prudent course of action to avoid the pitfalls currently plaguing their systems.