Microsoft has revealed that its long-awaited DirectStorage API for PCs will support PCIe 3.0 NVMe drives and PCIe 4.0 SSDs. This information was revealed in a presentation to developers at the Game Stack Live 2021 event. According to this DirectX Developer Blog, the actual presentation will be posted soon.

This is very welcome news but a surprise, since it was generally accepted that DirectStorage, which streamlines transfers between SSDs and graphics cards, was limited to the latest and fastest technology. Note, however, that it will not work with SATA drives. This is because SATA drives are not fast enough for what Microsoft has in mind. [Until Intel released Rocket Lake late last month, PCIe 4.0 drives were limited to AMD's Ryzen 3000 and 5000 platforms; machines with PCIe 4.0 drives will have faster data transfers and potentially faster load times. [Microsoft DirectStorage differs significantly from the concept proposed by Nvidia in its RTX I/OAPI in that it copies compressed data to system memory before copying it to GPU VRAM. Once stored in graphics card VRAM, the GPU can decompress the data much faster than the CPU; Nvidia's solution works in much the same way, but bypasses system memory entirely and copies the data directly from the drive to the graphics card.

In answering a question from one developer at the event, Microsoft stated that bypassing system memory is something they are looking into for the future of DirectStorage.

While there are no specific details on what hardware DirectStorage will support, Microsoft will support all DirectX 12 compatible hardware, although hardware that supports DirectX 12 Ultimate will be faster stated that it will support all DirectX 12-compatible hardware. So if you were able to get a reasonably up-to-date graphics card, you should be able to benefit from the improved way of accessing data when Windows comes with DirectX 12 Ultimate.

Microsoft DirectStorage will be in limited developer preview this summer and is expected to be in full release by the end of the year. being running on Xbox Series S/X means that games that use that API should be fairly easy to port should be able to do so.