A review of the Xbox Series X and a review of the PS5 have been published, and both are great machines. However, one of the things that sets the Xbox Series S and X apart from the PS5 is backward compatibility.

While Microsoft and Sony's next-gen machines have some degree of backward compatibility, the new Xbox's backward compatibility is far more complete.

And it turns out that this is no coincidence. According to Jason Ronald, Microsoft's director of Xbox program management, this is something Microsoft has been working hard on for four years.

"We've been working on the Xbox Series X and Series S since 2016," he told Inverse. 'Even before we had a processor, we were taking performance data from existing games and running them through a simulator on a next-generation chip. This allowed us to identify potential problems in the process, or even before production."

The company continued to test the game as the hardware advanced, making sure it performed as expected and improving aspects of the game with features like auto HDR.

As one might imagine, this takes time. And it is truly amazing how much work the company has put into something that has never been considered a top priority.

"Last year we ran tests on one game that took 16 to 24 hours," Ronald continued. We had an army of about 500 testers who went through every game in order of priority. If they found a problem, the backward compatibility team fixed it without developer involvement. We have a responsibility to ensure that these games continue to work reliably."

The results were indeed impressive, with only a handful of Xbox One games not working due to the lack of Kinect hardware integration.

The PS5 solution, on the other hand, is said to be more patchy. The official list of unsupported titles is very discreet, but Ubisoft suggests that this may not tell the full story. Furthermore, of course, the Xbox Series X supports some original Xbox and 360 games, but the PS5's backward compatibility begins and ends with the PS4.

And Microsoft may not be done with backward compatibility yet. Later in the interview, Ronald was asked about more vintage titles being added to the mix, and he did not rule it out. 'Yes, it's definitely something we're considering,' he said. 'There are some technical challenges, but a lot of times there are licensing issues. In some cases, the developer or publisher no longer exists. It's very, very difficult to even keep track of whose approval is needed."