DirectStorage: Optimizing dstorage.dll for Ultra-Fast Loading

The objective is to minimize the path length ($L_{path}$) that data travels, ensuring the NVMe -> PCIe -> GPU pipeline is free of legacy Windows File System bottlenecks.

1. Hardware Requirements for GPU Decompression

DirectStorage requires specific hardware to move from “Software Emulation” to “Hardware Acceleration.”

Component	Minimum Requirement	Technical Purpose
SSD	NVMe Gen 4 or Gen 5	High-speed IOPS ($>7000MB/s$) for parallel asset requests.
GPU	DirectX 12 Ultimate (RTX 20+/RX 6000+)	Required for Sampler Feedback and GPU-side decompression.
OS	Windows 11 24H2 / Windows 12	Includes the BypassIO feature for direct file access.

2. Optimizing the dstorage.dll Performance

While the game provides the DLL, Windows controls the environment it runs in. You can optimize the handshake between the game engine and the OS.

Step-by-Step Instructions:

1. Enable BypassIO: This is a kernel-level optimization that allows DirectStorage to skip the traditional file system filters.
   • Open PowerShell (Admin) and type:

fsutil bypassio state C:\

1. If it says “BypassIO is supported,” your system is optimized. If not, check if an old Antivirus or Disk Filter is blocking it.
2. GPU Driver Priority: Modern drivers (NVIDIA 570.xx+ / AMD 26.x+) include specific DirectStorage optimizations. Set your Power Management Mode in the GPU control panel to “Prefer Maximum Performance” to ensure the GPU decompressor never enters a sleep state during load screens.

3. DirectStorage Diagnostic Check

In 2026, Windows includes a built-in diagnostic to check if your system is actually using the GPU for decompression rather than the CPU.

Step-by-Step Instructions:

1. Press Win + G to open the Xbox Game Bar.
2. Go to Settings > Gaming Features.
3. Check the DirectStorage section.
4. It should say: “GPU Decompression: Supported” and “BypassIO: Optimized.”

4. Technical Synergy: The “DirectStorage + ReBAR” Link

DirectStorage performance is heavily influenced by Resizable BAR (see our previous guide).

• When ReBAR is enabled, the GPU can map the entire asset pool directly into its memory.
• Our GameEngineer.net lab tests show that disabling ReBAR while using DirectStorage can actually increase load times because the CPU must act as a middleman for the VRAM address mapping ($V_{addr}$).