Microsoft is fundamentally redesigning NVMe drivers for Windows; initial tests show significant performance shifts

With Windows 11 25H2 and Windows Server 2025, Microsoft is fundamentally modernizing its NVMe storage stack. Instead of continuing to evolve the storNVMe.sys driver, a completely new implementation is being created based on the IoRing framework to reduce latency, use the CPU more efficiently, and enable significantly higher IOPS. storNVMe.sys was designed for maximum hardware compatibility over many Windows generations, resulting in a complex, interrupt-reliant architecture. The new driver lets the processor control storage operations more directly, preparing and bundling multiple requests to reduce latency and administrative overhead. Initial tests with multiple NVMe SSDs show strong gains for random reads and in some cases new peak IOPS, which could benefit databases and virtualization. Sequential transfer benchmarks sometimes perform worse today, likely because the implementation currently focuses on parallel I/O workloads and needs further optimization. The driver is included as a preview in current Windows 11 25H2 and Windows Server 2025 builds but is not enabled by default; Microsoft is allowing testing while it refines the implementation. The redesign also lays groundwork for modern NVMe features such as zoned namespaces for large storage systems. Because the driver is not finalized and benchmark results vary, it is not recommended for production use until Microsoft completes optimizations and enables it officially.

Update: 23 Jun 2026