DirectStorage on PC: What It Changes for Game Loading

A fast NVMe SSD does not automatically make every PC game load faster. DirectStorage is a Windows API that game developers can build into a title to handle asset reads more efficiently. It can help supported games load and stream assets, but the result still depends on the game and the rest of the PC.

As of 24 June 2023, DirectStorage 1.1 had been available to developers for months. It added GPU decompression for game assets stored in a compatible format. The useful distinction is simple: the SSD is only one stage of the pipeline, and the game has to use the API.

Why a fast SSD can still wait

Modern games often load many small pieces of data, such as parts of textures and models, as a scene comes together. A fast drive can read that data quickly, but the game still has to request it, manage the requests and decompress the assets before the GPU can use them.

Microsoft's explanation of DirectStorage describes how older storage APIs made games manage requests one at a time. As modern games make more small requests, that overhead can limit how effectively they use a high-speed NVMe drive.

DirectStorage gives developers a different way to submit batches of requests in parallel, reduce overhead per request and control when the game hears that data is ready. It changes how a game moves asset data through the I/O pipeline; it does not raise the SSD's own rated transfer speed. Microsoft's stated goals are shorter waits and more detailed worlds that can stream as the player moves.

What the GPU decompression feature adds

Game data is often compressed to save storage space. It has to be decompressed before the game can use it. DirectStorage 1.1, released on 7 November 2022, added support for GDeflate and GPU decompression. When a game uses compatible compressed data and requests a GPU resource, the GPU can handle that decompression work instead of sending it all through the CPU.

Microsoft said GPU decompression was supported on DirectX 12 hardware with Shader Model 6.0. Hardware vendors could add their own optimisations, and the API could use the CPU when its GPU decompression path was unavailable. The game still needs to be built to use DirectStorage and compatible asset formats; installing the API does not convert older games automatically. Microsoft's DirectStorage 1.1 announcement describes the format and the fallback behaviour.

This can reduce CPU work in the parts of a game that use the feature. It does not promise higher frame rates. DirectStorage is an I/O and asset-loading feature, not a general rendering upgrade.

What Windows and storage does a player need?

Microsoft's March 2022 PC release announcement said DirectStorage was compatible with Windows 10. Microsoft recommended Windows 11 because its latest storage optimisations were built in. It also said players might see benefits with different storage devices, while an NVMe SSD would maximise I/O performance.

Those are general recommendations for the API. A specific game's requirements still take precedence. More importantly, a Windows setting cannot make an unsupported game use DirectStorage: support has to be part of the game. Check the game's requirements and release notes rather than looking for a system-wide DirectStorage switch.

What Forspoken's early test can tell you

When Forspoken launched on PC in January 2023, it became an early retail example of DirectStorage in a game. In February, PCWorld compared several drives using Forspoken's built-in, seven-scene loading benchmark. Its test machine used Windows 11 22H2, a Core i9-13900KF, an RTX 4090 and 32 GB of DDR5 memory. PCWorld reported that the faster PCIe 4.0 NVMe drives led the scene-loading results, while slower devices showed more variation across repeated runs.

That is an attributed test on one game and one high-end PC, not a Jitsumi benchmark or a prediction for every title. It shows why game-specific results matter: the drive, game engine, scene and test conditions all affect a loading result. A synthetic sequential-read number on an SSD box is not the same thing as a game's actual load time. PCWorld's Forspoken test explains its setup and methodology.

Should you upgrade for DirectStorage?

Before buying storage for this feature:

1. Check whether the game you want to play actually supports DirectStorage.
2. Read that game's own Windows and storage requirements.
3. If you are choosing a drive anyway, an NVMe SSD is the route Microsoft recommended for maximising I/O. Check that your PC supports the drive.
4. Compare real tests from the same game and benchmark scene, with the drive type and test conditions stated. Treat results from one game as an example, not a guarantee.

If no game you play uses DirectStorage, buying a faster SSD will not add the feature to those games. If you already have an NVMe drive, the first thing to check is whether a supported game is installed on it. You do not need to buy a top-tier drive solely because a game mentions DirectStorage.

This explainer reflects information available by 24 June 2023. DirectStorage support and game requirements can change as developers release new titles and updates.

Sources

• Microsoft: DirectStorage is coming to PC
• Microsoft: DirectStorage API now available on PC — 14 March 2022
• Microsoft: DirectStorage 1.1 now available — 7 November 2022
• PCWorld: Tested: Microsoft’s DirectStorage signals the sunset of SATA SSDs — 2 February 2023