Rumors regarding the consoles first emerged in early 2019, with the line as a whole codenamed "Scarlett", and consisting of high-end and lower-end models codenamed "Anaconda" and "Lockhart" respectively. Internally, Microsoft had been satisfied with the two-console approach for the Xbox One, and planned a similar approach for the fourth generation Xbox, with the target for the high-end model to at least double the performance of theXbox One X. The high-end model was first teased duringE3 2019under the title "Project Scarlett", while its name and design as Xbox Series X was unveiled duringThe Game Awardslater in December. In September 2020, Microsoft unveiled the lower-end model as the Xbox Series S.
The Xbox Series X has higher end hardware, and supports higher display resolutions (up to8K resolution) along with higher frame rates and real-timeray tracing; it also has a high-speedsolid-state driveto reduce loading times. The less expensive Xbox Series S uses the same CPU, but has a less powerful GPU, has less memory and internal storage, and lacks an optical drive. Both consoles arebackwards compatiblewith many previous generation Xbox games, controllers, and accessories. And, as part of a program Microsoft calls "Smart Delivery", many previous generation games feature upgraded graphics on the Series X/S at no additional charge. The consoles are also compatible with the gaming subscription serviceXbox Game Pass, as well as the cloud game-streaming platformXbox Game Pass cloud gaming.