Xbox Series X backwards compatibility explained: Xbox spent 500,000 hours testing backwards compatibility! Which original Xbox, Xbox 360, and Xbox One titles run on the Series X?

One of the main features Microsoft has utilised in its Xbox Series X marketing is the ability to play older titles on its next-gen console at no extra cost.

Microsoft sums up its backwards compatibility offering like so: "Our commitment to compatibility means existing Xbox One games, including backward-compatible Xbox 360 and original Xbox games, look and play better than ever before [on Xbox Series X].

Aside from just porting these games over, Microsoft has also promised they will receive significant upgrades to make them more in line with a next-gen experience when possible.

READ MORE: Where to pre-order the Xbox Series X console

If you're wondering what this actually means, keep reading for the full lowdown on Xbox Series X backwards compatibility.

Xbox tested backwards compatibility for 500,000 hours!

In a recent tweet, Xbox's Jason Ronald revealed that "all Xbox, Xbox 360 and Xbox One games playable on Xbox One today, except for the handful that require Kinect, will be available – and look and play better – on Xbox Series X|S at launch."

This is no small feat, given the number of titles included in this group of backwards compatible games. As such, Ronald also revealed that this comes after "500K+ hours of testing" by game testers and QA teams.

Xbox blog post reveals new backwards compatibility details!

A recent Xbox blog post has further clarified some of the ways previous titles will receive boosts in the next-gen.

Xbox is implementing a new feature called 'Auto HDR'. This will "automatically adds HDR enhancements to games which only shipped with SDR" without impacting the original art-style of the game and at no cost to the CPU or GPU.

High Dynamic Range (HDR) is a feature first introduced to the Xbox family with the Xbox One S. It allows for "a game to render a much larger range of brightness values and colors."

Aside from these enhanced visual upgrades, the Xbox Series X/S will utilise new, custom designed technology to double the frame rate on select titles such as Fallout 4, bringing the framerate up from 30fps to the much better 60fps.

Finally, the blog post also confirmed that cloud save data from as far back as the Xbox 360 will also be compatible with the Xbox Series X and Series S consoles, meaning that if you never quite finished playing the Halo campaigns, you can pick them back up on the next-gen consoles.

READ MORE: PS5 and Xbox Series X both have limited storage: How can I increase my console storage for more games?

Xbox Series X backwards compatibility explained

Xbox Series X backwards compatibility has been explained in a detailed new blog post on Microsoft's official Xbox Wire news website, and it makes for mouthwatering reading.

Credited to Jason Ronald, Director of Program Management for Xbox Series X, the blog post makes it clear that Microsoft doesn't just want to bring back your old games - it wants to make those Xbox One and Xbox 360 titles better than ever, with a helping hand from the Xbox Series X hardware!

The blog states, "As gamers, we also know how important it is to preserve and respect our gaming legacies. Your favorite games and franchises, your progression and achievements, and the friendships and communities you create through gaming should all move with you across generations."

One thing the blog makes a point of explaining is this: "Not only should gamers be able to play all of these games from the past, but they should play better than ever before [on Xbox Series X].

"Backwards compatible games run natively on the Xbox Series X hardware, running with the full power of the CPU, GPU and the SSD. No boost mode, no downclocking, the full power of the Xbox Series X for each and every backward compatible game.

"This means that all titles run at the peak performance that they were originally designed for, many times even higher performance than the games saw on their original launch platform, resulting in higher and more steady frame rates and rendering at their maximum resolution and visual quality. Backwards compatible titles also see significant reductions in in-game load times from the massive leap in performance from our custom NVME SSD which powers the Xbox Velocity Architecture."

This tech will be able to add HDR to games that didn't originally have it, and it will be able to boost frame rates up to 120FPS for select classic titles. Basically, the future is bright for your old games!

READ MORE: Is Sony making a PS5 backwards compatibility mistake?