What is ray tracing?

If you’re in the market for a new graphics card, you may have heard the term ‘ray tracing’ being bandied about. It’s a (relatively) new and (very) exciting development in computer game graphics which should lead to more realistic looking games than ever.

But what is ray tracing, and is it worth it? Read on to find out.

Ray tracing is a way of dynamically rendering light and shadows, by simulating and tracking every ray of light in the virtual world. It’s been used to add realism in animated films for many years, but Nvidia has implemented ray tracing technology into many of its graphics cards so that games makers can take advantage – and in real-time.

That means that things like shadows will map realistically as characters move, and reflections will appear in glass and puddles as you walk through a game world.

It’s a subtle change, but one that definitely adds to realism, as the video below showing ray tracing enabled and disabled on Metro Exodus demonstrates.

While ray tracing is particularly aimed at newer games, it can be applied to older titles – and, in fact, the effects are so demanding that in some ways it works better in such games. Here’s 1997’s Quake 2 getting a ray-tracing boost:

Is ray tracing worth it?

Having tried the Quake 2 ray tracing demo on GeForce Now out of curiosity, I was surprised at how quickly I stopped noticing the fancy effects once I stopped looking for them.

It’s undoubtedly pretty, but the impact on frame rate is massive as the below video of Shadow of the Tomb Raider demonstrates. The title loses around a third to half the frames per second (fps) depending on how busy the effects are, and the effect isn’t that impressive.

But, in truth, modern story-driven games have actually gotten quite good at faking accurate lighting, because reflections can be programmed in for each scene. In a game where there’s infinite scenes, ray tracing could be far more important – something like Minecraft, for example, where the game world can’t be anticipated by designers.

And right on cue…

Can I turn off ray tracing?

Yes – and in fact, it’s more a case of enabling it for the handful of games that currently support it. So you’ll have to opt in for the enhanced effects (and reduction in frame rate) rather than needing to to opt out.

What graphics cards support ray tracing?

For now, only a handful of graphics cards support ray tracing, all of them made by Nvidia. Originally, only cards carrying the RTX name – the RTX 2060, 2070 and 2080 range – supported the feature, but last year Nvidia added support for ray tracing in older cards. Though obviously their generally slower performance means they won’t do it as well in most games.

Here is the full list ray supporting cards as of June 2020:

GeForce RTX 2080
GeForce RTX 2070
GeForce RTX 2060
GeForce GTX 1660 Ti
GeForce GTX 1660
Nvidia Titan Xp (2017)
Nvidia Titan X (2016)
GeForce GTX 1080 Ti
GeForce GTX 1080
GeForce GTX 1070 Ti
GeForce GTX 1070
GeForce GTX 1060 6GB

Can I use ray tracing with AMD cards?

Not yet. But apparently AMD graphics cards with ray tracing support will arrive this year in some form or other – and the Xbox Series X and PlayStation 5, which both use AMD graphics, will also benefit.

What is ray tracing?