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Windows Server 2025 Native NVMe: Storage Stack Overhaul and Benchmark Results

March 6, 2026

On December 15, 2025, Microsoft made headlines with the announcement of native NVMe support in Windows Server 2025. While NVMe has been a well-established storage format for years, its integration into the Windows Server architecture marks a significant evolution in how data is managed and accessed. This transition is not merely a matter of compatibility; it represents a fundamental shift in the underlying storage framework.

What Does “Native NVMe” Even Mean?

Historically, Windows operating systems have relied on the Small Computer System Interface (SCSI) to manage storage commands. This standard, which dates back to the early 1980s, has served as a bridge between various storage devices and the operating system. However, this reliance on SCSI has often meant sacrificing the performance and scalability benefits offered by newer technologies like NVMe.

The Old Way

The previous approach to I/O operations involved a multi-step translation process:

  1. Read and write operations initiated at the filesystem level.
  2. Commands were directed to the Disk.sys driver.
  3. Disk.sys translated these commands into SCSI commands.
  4. Storport received the SCSI commands and relayed them to the appropriate Miniport driver.
  5. The Miniport driver then communicated with the storage device, translating commands once more.

This method, while effective, introduced latency and limited the potential for harnessing the full capabilities of modern storage solutions.

The New Standard

With Windows Server 2025, Microsoft has revamped its storage architecture. The new system replaces Disk.sys with NVMeDisk.sys, allowing for a more direct communication pathway:

  1. Read and write operations still begin at the filesystem level.
  2. Commands are now sent directly from NVMeDisk.sys to the new StorMQ code within Storport.
  3. StorMQ generates NVMe commands and communicates directly with the hardware.

This streamlined process eliminates unnecessary translation layers, enhancing performance and reducing CPU resource usage. The architecture also embraces NVMe specifications such as namespaces and plug-and-play support, facilitating better compatibility with a range of storage devices.

Ready to Test?

During the SNIA Developer Conference on September 16, 2025, Scott Lee highlighted Microsoft’s collaboration with vendors to develop drivers for various devices, indicating that enhancements to StorMQ are imminent. Although the feature was announced as generally available, enabling it requires a registry modification, which should be approached with caution.

Warning: Modifying the registry incorrectly can lead to significant issues. It is advisable to test this feature on non-critical servers first. Some users have reported complications with NVMe drives when deduplication is enabled, though a fix from Microsoft is anticipated.

Testing Native NVMe on Windows Server 2025

Our evaluation of native NVMe on Windows Server 2025 utilized a robust testing platform featuring dual 128-core AMD EPYC 9754 CPUs and 768GB of DDR5 memory. To assess the new storage stack’s performance, we employed sixteen 30.72 TB Solidigm P5316 NVMe SSDs in a JBOD configuration, conducting FIO benchmarks across various block sizes.

Note: An interim improvement unrelated to native NVMe has already been released, potentially affecting the performance of the non-native storage stack.

Highlights

  • Massively increased 4K and 64K random read bandwidth and IOPS
  • Lower 4K and 64K random read latency
  • Significant decreases in CPU usage for sequential reads and writes across varying block sizes
Metric Random 4K Random 64K Sequential 64K Sequential 128K
Non-Native Native Non-Native Native Non-Native Native Non-Native Native
Read
Bandwidth (GiB/s) 6.1 10.058 74.291 91.165 35.596 35.623 86.791 92.562
IOPS 1,598,959 2,636,516 1,217,176 1,493,637 583,192 583,638 710,978 758,252
Average Latency (ms) 0.169 0.104 0.239 0.207 0.809 0.812 0.613 0.608
Total CPU Usage (%) 72.67 74.22 68.44 65.11 44.89 37.11 61.56 49.56

Analysis of Results

Our tests revealed a marked improvement in read speeds, particularly in the random 4K and 64K benchmarks, where we noted nearly 4 GiB/s and 16.9 GiB/s increases, respectively. Sequential read operations also showed promising results, with an uptick of about 5.8 GiB/s in bandwidth.

Interestingly, write operations did not exhibit the same level of enhancement, with only a modest increase in 64K sequential writes. However, the consistency of results across both storage stacks suggests that the new architecture maintains performance levels where it does not improve.

Latency metrics further supported the advantages of the new stack, with significant reductions in average random read latency. For instance, random 4K read latency decreased by 38.46%, while random 64K read latency saw a 13.39% drop. Sequential read operations remained stable, but random and sequential write operations experienced slight increases in latency.

Moreover, our analysis indicated a substantial decrease in CPU usage during sequential read and write tests, particularly for 64K and 128K operations. These findings align with Microsoft’s claims of improved efficiency, suggesting that while throughput may not always increase, the overall resource utilization is optimized.

Takeaways

While variations in test results were observed, the data largely supports Microsoft’s assertions regarding enhanced read bandwidth, reduced latency, and lower CPU utilization. As this transition to a native NVMe framework represents a significant departure from traditional storage methodologies, Microsoft plans to implement native NVMe support by default in future Windows Server versions. For those eager to explore this new capability, a simple registry edit allows access to the benefits of the updated storage stack today, albeit with caution regarding potential risks.

The anticipation surrounding native NVMe’s default status in future releases is palpable, as stakeholders from the NVMe SSD, RAID card, and HBA sectors prepare to leverage these advancements for enhanced performance.

References

Winsage
Windows Server 2025 Native NVMe: Storage Stack Overhaul and Benchmark Results