The upcoming Xbox Series X will be compatible with four generations of Xbox games plus Xbox One accessories. Microsoft has also detailed its solution for storage expansion.

Xbox backwards compatibility
Xbox Series X will be inherently backwards compatible with Xbox One games since both - like PlayStation 4 and 5 - are based on PC hardware; so-called x86 architecture. Xbox 360 is built on a different architecture (PowerPC).

In addition, Microsoft says that Xbox Series X will run "thousands of your favorite games" from the original Xbox and Xbox 360.

However, Microsoft has not announced that its next console will be compatible with all previous generation games. It is not clear either if game discs will be supported or only digital purchases made through the online store.

- "At Xbox, we’ve made a promise to compatibility: you can expect thousands of your favorite games across four generations of gaming, your Xbox One gaming accessories, your Xbox gaming legacy, and industry-leading services like Xbox Game Pass to work with Xbox Series X," said Microsoft.



The company added that compatible games from previous generations will also benefit from the increased performance of Xbox Series X.

- "Backward compatible games will benefit from the power and performance of Xbox Series X, resulting in steadier framerates, faster load times, improved resolution and visual fidelity."

The next-gen game console will feature SDR-to-HDR up-conversion, the company said. This will let the user up-convert a game created in SDR (Standard Dynamic Range) to a form of artificial HDR look. Many TVs have similar capabilities.

Another aspect of backwards compatibility is 'Smart Delivery', which means that Xbox One games enhanced for Xbox Series X will be available free of charge if you have already bought the Xbox One version. However, there is a caveat. While Microsoft has pledged to support 'Smart Delivery' for all games developed by its own studies, outside studios are not required to support it. The studio behind upcoming Cyberpunk 2077 has announced that it will back the initiative.

Lastly, there is support for cross-platform multiplayer between Xbox Series X and the Xbox One series of consoles. We are awaiting further details.



SSD storage expansion card
Microsoft has confirmed that Xbox Series X will come with built-in 1TB SSD storage. Capacity can be expanded via a USB hard drive or a custom NVMe SSD module that looks a little like the memory card used in some early game consoles.

However, the USB hard drive will only let you play previous generation Xbox titles. The SSD module is required for Xbox Series X titles.

- "Previous generation Xbox titles can still be played directly from external USB 3.2 hard drives. However, to receive all the benefits of the Xbox Velocity Architecture and optimal performance, Xbox Series X, optimized games should be played from the internal SSD or Xbox Series X Storage Expansion Card," the company explained.

The SSD module will initially be available with 1TB capacity but additional options will be offered later. Pricing details were not announced.

Xbox Series X features
Backward Compatibility – At Xbox, we’ve made a promise to compatibility: you can expect thousands of your favorite games across four generations of gaming, your Xbox One gaming accessories, your Xbox gaming legacy, and industry-leading services like Xbox Game Pass to work with Xbox Series X. Backward compatible games will benefit from the power and performance of Xbox Series X, resulting in steadier framerates, faster load times, improved resolution and visual fidelity. Fans and game creators can feel confident they will be able to play and create the best version of their games on the Xbox Series X.

SDR to HDR Conversion – With Xbox Series X, existing Xbox games, including recent titles within the ID@Xbox program, that don’t already have native HDR support will get the next-gen treatment. Xbox Series X is able to leverage an innovative HDR reconstruction technique to enhance existing SDR games with no work from developers and no impact to available CPU, GPU or memory resources.

Smart Delivery – Smart Delivery is a new technology introduced with Xbox Series X that will ensure you always play the best version of the games you own for your console, across generations. All Xbox Game Studios titles that are optimized for Xbox Series X, including “Halo Infinite” will support Smart Delivery, providing the best available version for whichever console you choose to play on. For example, this means if you purchase the Xbox One version of a supported title, we will identify and deliver the best version of it to your Xbox One, as usual. If you decide to jump into the next generation with Xbox Series X, we will automatically provide the Xbox Series X optimized version of the game at no additional cost if and when it becomes available. Smart Delivery is available to all Xbox developers.

Xbox Series X Storage Expansion Card –  Built in partnership with Seagate, this 1 TB custom storage solution expands storage capacity of Xbox Series X with the full speed and performance of the Xbox Velocity Architecture Previous generation Xbox titles can still be played directly from external USB 3.2 hard drives. However, to receive all the benefits of the Xbox Velocity Architecture and optimal performance, Xbox Series X, optimized games should be played from the internal SSD or Xbox Series X Storage Expansion Card. 
 - Source: Microsoft