Following the Diablo IV beta in late March, some dataminers uncovered clear references to the Microsoft DirectStorage API in Blizzard's game files. The finding sparked speculation that Diablo IV would become the second game to support the API after Luminous Productions' Forspoken, but Blizzard never addressed that reference, and there was nothing in the final game to suggest the feature was enabled. However, a Blizzard spokesperson finally responded to PC Gamer, telling them the feature is indeed coming to Diablo IV in the future.
Microsoft DirectStorage debuted on Xbox Series S|X consoles as part of the so-called Xbox Velocity Architecture, a combination of hardware and software designed to 'reinvent the traditional I/O system' and ultimately lower loading times. DirectStorage's part as a low-level API is to allow fine-grain control on I/O queues, optimal prioritization, and low latency.
Microsoft said almost immediately that the API would come to PC, although it took quite a while before that happened. The Developer Preview appeared in July 2021, and version 1.0 was formally launched at GDC 2022. Microsoft continued working on the API, launching version 1.1 in November. This update added support for GPU-based decompression, which many developers had been waiting for.
However, it wasn't until January 2023 that PC gamers could finally test the technology with the release of Forspoken. To this day, it remains the only PC game to support DirectStorage, even after the release of yet another version of the API (1.2) this April. Interestingly, while Microsoft originally said that the technology's true potential would only be unleashed with SSDs (specifically NVMe ones), DirectStorage 1.2 adds the ability for developers to force a buffered I/O mode as a benefit for regular hard drives. That's doubly peculiar given that some games like Starfield and Cyberpunk 2077: Phantom Liberty are just dropping support for hard drives, requiring users to be equipped with SSDs.
At any rate, DirectStorage could certainly improve loading times in Diablo IV, although they are pretty quick even in the current state. There's no telling how long it'll take before Blizzard adds official support to the game, though.
A third developer announced its intention to support DirectStorage in March. Crytek said it would introduce the technology as part of a wider technical revamp of Hunt: Showdown, which will be updated to support AMD FidelityFX Super Resolution 2.1, High Dynamic Range (HDR) displays, and the latest CryEngine version (5.11). Just like with Diablo IV, there's currently no official word on when the update will be shipped.
source https://wccftech.com/directstorage-is-indeed-coming-to-diablo-iv-blizzard-confirms/