First benchmarks of Microsoft's DirectStorage 1.1 API running on Sabrent's Rocket 4 Plus-G PCIe Gen4 SSD have been published by Compusemble.
Microsoft DirectStorage 1.1 API Tested On Sabrent's Rocket 4 Plus-G PCIe Gen4 SSD
Back in August, Sabrent introduced its brand new Rocket Plus-G PCIe Gen4 SSDs for PC & console gamers. These SSDs are specifically optimized for Microsoft's DirectStorage API which aims to bring console-level loading times to the PC platform. Microsoft also introduced GPU decompression with its v1.1 of the DirectStorage API which will be shipping with the latest AAA titles such as Forspoken in early 2023.
Upon initial release, DirectStorage for PC enhanced data transfers to the CPU, but the 1.1 release also improves decompression by allowing devs to offload it on the GPU. Here is Microsoft’s more detailed description of what exactly DirectStorage 1.1 and GPU decompression brings to the table.
“ames require massive amounts of data to build immersive worlds – every character, object, and landscape […] adds up to hundreds of gigabytes of data. To reduce the overall package size of a game, these assets are compressed. When a game is run, the assets are transferred to system memory, where the CPU decompresses the data before it is finally copied into GPU memory to be used as needed. The transfer and decompression of these assets on gaming devices contribute heavily to load times and limit how much detail can be included in open-world scenes.
DirectStorage 1.0 improves the data transfer part of this process. Advances in Windows 11 combined with DirectStorage allow developers to make use of the higher bandwidth of NVMe drives. DirectStorage-enabled games installed on NVMe drives should expect to see reductions in load times by up to 40%. After enhancing this part of the pipeline, developers will want to improve decompression performance next.
Typically, decompression work is done on the CPU because compression formats have historically been optimized for CPUs only. We are offering an alternative method in DirectStorage 1.1 by moving the decompression of those assets to the GPU instead – known as ‘GPU decompression.’ Graphics cards are extremely efficient at performing repeatable tasks in parallel, and we can utilize that capability along with the bandwidth of a high-speed NVMe drive to do more work at once. As a result, the amount of time it takes for an asset to load decreases, reducing level load times and improving open world streaming.
In the benchmarks, we can see that the Sabrent Rocket Plus-G PCIe Gen4 SSD offers over twice the bandwidth versus a PCIe Gen3 SSD after GPU decompression. The majority of the bandwidth here is due to the Gen4 protocol but the DirectStorage API also uplifts the performance. Compared to a high-end WD_Black SN850X Gen4 SSD, the same Rocket 4 Plus-G PCIe Gen4 SSD comes out a good bit ahead in NVMe SSD Read speeds prior to GPU decompression.
What's important about the Expanse benchmark is that it measures the sustained performance in a Microsoft DirectStorage API workload. We can see that the Sabrent Rocket Plus-G PCIe Gen4 SSD sustains a higher bandwidth throughout the benchmark and according to Intel, such sustained B/W numbers will be useful in future DirectStorage games. The Phison IO+ Firmware also plays a very important role in sustaining higher bandwidth since it's specifically tuned for the DirectStorage API.
Microsoft DirectStorage API is available on PCs right now but besides some benchmark demos, it hasn't been introduced in a AAA game or application yet. We will have to wait till 2023 before we get to see the API actually in action.