Microsoft unveiled the XBOX Series X to much acclaim in mid-2020, introducing new performance technologies to the Xbox ecosystem alongside substantially upgraded hardware. One part of the suite of features known as XBOX Velocity Architecture revealed during the showcase was DirectStorage, an API that allows GPUs to stream data into graphics memory direct from high-speed NVMe storage, bypassing major bottlenecks and greatly increasing texture streaming bandwidth. The tech. was announced as coming to Windows in September 2020, and has now finally made it to a public SDK release.
The 2021 Developer preview outlined the core features of DirectStorage as follows:
- The new DirectStorage API programming model that provides a DX12-style batched submission/completion calling pattern, relieving apps from the need to individually manage thousands of IO requests/completion notifications per second,
- GPU decompression providing super-fast asset decompression for load time and streaming scenarios (coming in a later preview),
- Storage stack optimizations: On Windows 11, this consists of an upgraded OS storage stack that unlocks the full potential of DirectStorage, and on Windows 10, games will still benefit from the more efficient use of the legacy OS storage stack.
- GPU decompression providing super-fast asset decompression for load time and streaming scenarios (coming in a later preview),
- Storage stack optimizations: On Windows 11, this consists of an upgraded OS storage stack that unlocks the full potential of DirectStorage, and on Windows 10, games will still benefit from the more efficient use of the legacy OS storage stack.
With this release game developers will be able to utilise the DirectStorage API, offloading workload from the CPU and generally improving data streaming bandwidth. This is just the first release however; more features are planned for the future with a priority on GPU decompression and further optimisations.
Sony leveraged a DirectStorage-like technology on Ratchet and Clank: Rift Apart for the Playstation 5, which at present is the clearest and most effective use high-speed texture streaming to unlock seamless environmental transitions and eliminating load screens. It remains to be seen whether such developments will be seen in AAA game releases on PC, but here's hoping.
The DirectStorage API is available on both Windows 10 and 11, but for now only the latter operating system incorporates the latest kernel optimisations. All DirectX 12 GPUs should support the tech but DirectX 12 Ultimate compatible hardware (GeForce RTX 20-series and Radeon RX 6000-series or better) will be the best fit.
More information on the technology can be found at the announcement blog post.
