Microsoft has finally unleashed the Xbox One X and it is dubbed the "most powerful" games machine yet.

You can read our full, in-depth review here: Xbox One X review: Stacked with power and potential. But, how does it rate alongside the cheaper, existing Xbox One S?

We look at just how different the two are to give you an idea of which you might want to adopt come Christmas.

One of the major differences between the two machines comes with graphical hardware and the ability to render full 4K visuals.

The Xbox One S is capable of up to 1080p graphics running at 60fps (as on games such as Forza Horizon 3). Not all games achieve those heady heights, but its 12 GCN compute units, running at 914MHz can reach it. The console also upscales all video output to 4K for compatible TVs, but games do not run in Ultra HD natively.

Xbox One X, on the other hand, is capable of full 4K visuals running at 60fps (as on games such as Forza Motorsport 7), thanks to new graphics processing that consists of 40 customised compute units running at 1.172GHz. That's much more powerful and faster than the currently available machine.

The new console is also compatible with games featuring HDR (High Dynamic Range) - a rapidly expanding list. The Xbox One S already has that functionality.

Like with the graphics, Xbox One X is much more powerful than the Xbox One S in central processing. It runs on eight custom x86 cores, clocked at speeds of 2.3GHz. The Xbox One S also has eight cores but they are slower, running at 1.75GHz.

The One X also bosses things in RAM. There is 12GB of GDDR5 RAM with bandwidth of up to 326GB/s. The Xbox One S has 8GB of DDR3 RAM and 32MB of ESRAM, with bandwidth of 68GB/s and 219GB/s respectively.

The upshot of this is that developers get far more memory and speeds of processing to play with on Xbox One X.

The great news for Xbox One S owners is that, at present, Microsoft is committed to making the same games for Xbox One S and Xbox One X (and the original Xbox One come to that). You buy an Xbox game and it'll work on all three consoles, albeit with different grades of performance.

One X versions, therefore, have the potential to be far better graphically than their Xbox One S counterparts - with greater resolution, draw distances and the like. It's something Microsoft calls "enhanced". However, the gameplay technically remains the same. As does the price considering the game is the same bought copy.

It's a similar deal with the PS4 Pro. All PlayStation 4 games work on Pro and the standard PS4, they just look better on the Pro - for the most part.

By doing this, Microsoft ensures that the One X launches with an enormous back catalogue of Xbox One games available from the off. It will also be compatible with backwards compatibility for Xbox 360 and original Xbox games.

The Xbox One S was the first games console to offer 4K Ultra HD Blu-ray playback, with HDR picture tech to boot.

This is something the Xbox One X boasts too, with even better performance, we have found, and faster loading times.

All other major streaming apps and services are on board too, including Netflix and Amazon Video, both running supported shows and movies in 4K HDR. Dolby Vision isn't supported on either machine, although Dolby Atmos for extra surround sound channels is.

Here's the million dollar question - almost literally: how much more does Xbox One X cost?

It's not cheap. It costs $499 in the States and £449 in the UK.

In contrast, the current Xbox One S can be bought for around £200 with a game (the 500GB version anyway). A version with a 1TB hard drive can be snagged for around £250.

They are both available to buy now.

There is little doubt that Xbox One X is a more powerful, more graphically competent games console than the Xbox One S, but you have to pay a premium price for such a premium machine.

If you are content with Full HD gaming, the Xbox One S is an excellent games machine and 4K Blu-ray player for just £200. Hardcore gamers and those looking to futureproof their setup might choose to invest the extra, however.