Microsoft DirectStorage 1.1 API was tested using a Sabrent Rocket 4 Plus-G PCIe Gen4 SSD running the most recent Phison IO+ firmware.


Sabrent’s Rocket 4 Plus-G PCIe Gen4 SSD has been tested with Microsoft DirectStorage 1.1 API.

Sabrent introduced its new Rocket Plus-G PCIe Gen4 SSDs for PC and console gamers in August. These SSDs have been designed specifically for Microsoft’s DirectStorage API, which aims to bring console-level loading times to the PC platform. Microsoft also added GPU decompression to its DirectStorage API v1.1, which will ship with the latest AAA titles like Forespoken in early 2023.

DirectStorage for PC initially improved data transfers to the CPU, but the 1.1 release also improves decompression by allowing developers to offload it to the GPU. Here’s a more detailed explanation of what DirectStorage 1.1 and GPU decompression bring to the table.

“To create immersive worlds, ames require massive amounts of data – each character, object, and landscape […] adds up to hundreds of gigabytes of data. These assets are compressed to reduce the overall package size of a game. When a game is launched, the assets are transferred to system memory, where the CPU decompresses the data before copying it into GPU memory to be used as needed. The transfer and decompression of these assets on gaming devices significantly increases load times and limits the amount of detail that can be included in open-world scenes.

DirectStorage 1.0 enhances the data transfer portion of the process. Because of advancements in Windows 11 and DirectStorage, developers can now take advantage of the higher bandwidth of NVMe drives. Load times for DirectStorage-enabled games installed on NVMe drives should be reduced by up to 40%. Developers will want to improve decompression performance after improving this part of the pipeline.

Decompression work is typically performed on the CPU because compression formats have historically been optimised for CPUs only. In DirectStorage 1.1, we provide an alternative method by relocating the decompression of those assets to the GPU, which is known as ‘GPU decompression.’ Graphics cards are extremely efficient at performing repeatable tasks in parallel, which we can combine with the bandwidth of a high-speed NVMe drive to do more work at once. As a result, the time it takes for an asset to load decreases, resulting in faster level load times and better open world streaming.”

After GPU decompression, the Sabrent Rocket Plus-G PCIe Gen4 SSD offers more than twice the bandwidth of a PCIe Gen3 SSD, according to the benchmarks. The Gen4 protocol accounts for the majority of the bandwidth here, but the DirectStorage API also improves performance. In terms of NVMe SSD Read speeds before GPU decompression, the Rocket 4 Plus-G PCIe Gen4 SSD outperforms the high-end WD Black SN850X Gen4 SSD.

The Expanse benchmark is significant because it measures sustained performance in a Microsoft DirectStorage API workload. We can see that the Sabrent Rocket Plus-G PCIe Gen4 SSD maintains a higher bandwidth throughout the benchmark, and such sustained B/W numbers, according to Intel, will be useful in future DirectStorage games. Because it is specifically tuned for the DirectStorage API, the Phison IO+ Firmware also plays an important role in sustaining higher bandwidth.

Microsoft DirectStorage API is now available on PCs, but aside from some benchmark demos, it has yet to be used in a AAA game or application. We will have to wait until 2023 before we see the API in action.

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