Back in March 2022, Microsoft formally debuted the DirectStorage 1.0 API that enables direct interactions between a GPU and a storage device; thereby reducing the processing load of the storage stack on the CPU and main memory. This release, however, lacked a killer feature that's available to consoles—asset decompression. With the lukewarm response from game developers to DirectStorage 1.0 for PC, Microsoft has finally updated the API, introducing the feature with DirectStorage 1.1.

With this feature, your GPU can not only directly fetch game assets from the storage device (an SSD that uses either NVMe or AHCI protocols), but also pull them in their natively-stored compressed state. These assets are then decompressed by the GPU using compute shaders, and the decompressed assets remain in the video memory. This will directly impact game loading times, as asset decompression no longer involves the CPU. Its impact on the game's framerate will be minimal, as the API mainly accelerates game loading times, not gameplay itself. Game assets are organized pieces of data such as textures, 3D model files, music, sound effects—pretty much all of the individual pieces of content that make up a 3D scene.File compression (and decompression) remains a compute-heavy workload that benefits from parallelism, and here the GPU and its faster memory help greatly. Once the relevant assets are committed to video-memory, the remaining data from the asset containers are purged from video memory to make room for the rest of the game's memory load. Microsoft in its tech demo example showed how a 3D scene's assets were loaded in 0.8 seconds with DirectStorage 1.1, compared to 2.36 seconds without it. This is just a synthetic example, you can imagine the impact on much larger AAA games that take dozens of seconds to load levels, even with NVMe SSDs. The hold-up here is not the storage device, but the CPU trying to decompress relevant assets.

Along with DirectStorage 1.1, Microsoft is introducing GDeflate, a file compression format for game assets, developed by NVIDIA, and is working with all PC GPU manufacturers, including AMD and Intel, to add support for this file format through graphics driver updates. The format is optimized for highly parallelized compression and decompression methods over a large number of threads, which make them better optimized for GPUs. This doesn't necessarily mean that all games have to use GDeflate in order to take advantage of GPU-accelerated asset decompression over DirectStorage 1.1, it's just an added optimization for game developers working on new projects. Patching already-released games to have GDeflate would involve redistributing the entire game asset load (which is still fine if the developer chooses to).

Microsoft plans to release DirectStorage 1.1 to game developers toward the end of 2022. The first games released or patched with DirectStorage 1.1 support should start coming out in 2023.