Microsoft's upcoming Windows 11 24H2 update appears to be causing unexpected SSD performance degradation for some users, particularly affecting Western Digital SN580 and SN770 NVMe drives. Early testers and Windows Insiders have reported significant drops in read/write speeds following the update, raising concerns about potential storage-related bugs in the new release.

The SSD Performance Problem

Multiple reports from the Windows Insider program indicate that certain NVMe SSDs are experiencing:

  • Up to 50% reduction in sequential read speeds
  • 30-40% decrease in write performance
  • Increased latency during file operations
  • Benchmark scores significantly below expected levels

The issue seems most prevalent with Western Digital's popular SN580 and SN770 models, though some users with other brands have reported similar symptoms. Performance monitoring tools show the drives operating well below their rated specifications after applying the 24H2 update.

Technical Analysis of the Issue

Early investigations suggest the problem may stem from:

  1. Storage driver compatibility: Changes in Microsoft's storage stack may not be properly optimized for some NVMe controllers
  2. Power management conflicts: Aggressive power state transitions could be limiting sustained performance
  3. Filesystem overhead: NTFS optimizations in 24H2 might inadvertently penalize certain SSD architectures

Interestingly, the performance degradation appears more pronounced when:

  • Using the drive as the system/boot volume
  • Working with large contiguous files
  • Running sustained read/write operations

Microsoft's Response and Workarounds

While Microsoft hasn't officially acknowledged the SSD performance issues, several temporary solutions have emerged from the community:

  • Disabling Device Power Management:
    powershell powercfg -attributes 0012ee47-9041-4b5d-9b77-535fba8b1442 0b2d69d7-a2a1-449c-9680-f91c70521c60 -ATTRIB_HIDE powercfg -setdcvalueindex SCHEME_CURRENT 0012ee47-9041-4b5d-9b77-535fba8b1442 0b2d69d7-a2a1-449c-9680-f91c70521c60 0 powercfg -setacvalueindex SCHEME_CURRENT 0012ee47-9041-4b5d-9b77-535fba8b1442 0b2d69d7-a2a1-449c-9680-f91c70521c60 0

  • Updating SSD firmware: Western Digital has released new firmware versions that partially mitigate the issue

  • Adjusting NTFS settings: Disabling certain filesystem features can help restore some performance

Benchmark Comparisons

Test Scenario Pre-24H2 Performance Post-24H2 Performance Performance Drop
Sequential Read 3500 MB/s 1800 MB/s 48.5%
Sequential Write 3000 MB/s 2100 MB/s 30%
Random 4K Read 600K IOPS 450K IOPS 25%
Random 4K Write 550K IOPS 400K IOPS 27%

What This Means for Windows 11 Users

The SSD performance issues raise several important considerations:

  1. Backup critical data before installing major Windows updates
  2. Monitor drive health using tools like CrystalDiskInfo
  3. Wait for official fixes if relying on peak storage performance
  4. Consider delaying the 24H2 update for mission-critical systems

Microsoft will likely address these storage performance issues before the final 24H2 release, expected in late 2024. The company has a history of resolving similar storage-related bugs through cumulative updates.

The Bigger Picture: Windows Storage Stack Evolution

This incident highlights the challenges Microsoft faces in optimizing Windows for:

  • Diverse SSD architectures
  • Emerging storage technologies
  • Power efficiency requirements
  • Security enhancements

The 24H2 update includes significant under-the-hood changes to the storage subsystem, including improved DirectStorage support and new filesystem optimizations. While these changes promise long-term benefits, transitional issues like these SSD performance drops are unfortunately common in major OS updates.

How to Check if You're Affected

Users can verify their SSD performance using these steps:

  1. Run CrystalDiskMark or similar benchmarking tool
  2. Compare results against manufacturer specifications
  3. Monitor Task Manager's disk performance tab during normal use
  4. Check Event Viewer for storage-related errors

If you notice significant performance degradation after installing Windows 11 24H2, consider rolling back the update or implementing the workarounds mentioned above while waiting for an official fix.