Xbox Velocity Architecture Explained by Microsoft

The Xbox Velocity Architecture has remained a mystery to many. Though Microsoft markets it as a game-changing feature of Series X, they had not clarified exactly what it does.

That is until Jason Ronald, Director of Program Management on Xbox Series X, wrote an article on Xbox Wire. The article details the four main pillars of the Velocity Architecture. The pillars themselves are not very self-explanatory, so here are a few details.

The SSD

The custom NVME SSD is the foundation of the Xbox Velocity Architecture. Using this SSD, the Xbox Series X can leverage 2.4Gb/s of raw I/O throughput. More than 40x that of the Xbox One. Jason has this to say about the SSD: “The custom NVME SSD in Xbox Series X is designed for consistent, sustained performance as opposed to peak performance. Developers have a guaranteed level of I/O performance at all times and they can reliably design and optimize their games removing the barriers and constraints they have to work around today.” While the Xbox Series X will only have 1TB of storage built-in, you will be able to purchase an expansion drive, designed by Seagate, that Jason clarifies will be able to leverage the same performance as the internal drive.

Decompression

The second pillar of the Xbox Velocity Architecture is Hardware Accelerated Decompression. Game developers compress file sizes to minimize download time and storage required. Within the Series X, however, there is support on the hardware level for the industry-standard LZ decompressor. It also contains a brand new, proprietary algorithm specifically designed for texture data named BCPack. Here is what Jason says in the article: “Xbox Series X provides the best of both worlds for developers to achieve massive savings with no loss in quality or performance. Assuming a 2:1 compression ratio, Xbox Series X delivers an effective 4.8 GB/s in I/O performance to the title, approximately 100x the I/O performance in current generation consoles.”

API’s

The simplest explanation of an API is it allows two pieces of software to communicate. In regard to the Xbox Series X, this means the game and the software in the console. According to Jason, these API’s have not improved very much over the last 30 years. This was the reasoning behind the new API inside Series X. Jason continues to explain. “We added a brand new DirectStorage API to the DirectX family, providing developers with fine-grain control of their I/O operations empowering them to establish multiple I/O queues, prioritization and minimizing I/O latency.”

Sampler Feedback Streaming (SFS)

Sampler Feedback Streaming is a brand new method of rendering game textures. They render at far less quality the further away the player is. The resolution then increases the closer the player gets. Jason details the final pillar by saying. “We were able to create and add new capabilities to the Xbox Series X GPU which enables it to only load the sub-portions of a mip level into memory, on-demand, just in time for when the GPU requires the data. This innovation results in approximately 2.5x the effective I/O throughput and memory usage above and beyond the raw hardware capabilities on average”

This means that on Xbox Series X, games should require less storage and download time. Depending on how the developer optimizes the game, as well as what engine the game is using, with the Xbox Velocity Architecture, games could perform above what’s expected from the raw hardware. The article by Jason Ronald provides clarity on one of Xbox Series X’s many new features. Jason concludes the article by speaking on how the Xbox Velocity Architecture will impact gamers and developers. “We expect significant innovation throughout the next generation as this revolutionary new architecture enables entirely new scenarios never before considered possible in gaming.”

You can read the full article here. The Xbox Games Showcase is coming up next week, which you can read about in this article.