Smartphone ray tracing graphics are here, but is it the real deal?

While there was a lot to sniff at Qualcomm’s announcement of its Snapdragon 8 Gen 2 platform, the headline-grabbing new feature was undoubtedly smartphone ray-traced graphics support. Qualcomm adds support for hardware-based ray tracing to Mediatek’s Dimensity 9200 and Samsung’s Exynos 2200, opening the door to fancy new graphics effects for mobile games.

With 2023 flagship phones set to support this feature almost everywhere, will it be the year mobile gaming stops playing second fiddle to console and PC graphics?

Well, yes, but also no. Smartphone ray tracing is undoubtedly a nice feature that will in all likelihood lead to fancier graphical effects and games. There are still a few hurdles to be cleared, however, so a ray tracing reality check is in order.

It’s important to acknowledge here that ray tracing is a graphical term that encompasses a wide range of possible implementations. You can think of these as “layers” of ray tracing, each with their own graphics benefits and associated performance costs. Just because smartphones support ray tracing doesn’t mean games will look the same as they do on console and PC.

Ultimately, it boils down to whether you can render an entire scene with computationally intensive ray tracing, or go for a hybrid approach that only uses ray tracing for some effects. Given that PCs and consoles still take a hybrid approach, we’re definitely looking at the latter in the smartphone space. At the high-end, caustics can map the way light and reflections bounce off curved surfaces like water or glass, while less sophisticated implementations can improve the accuracy of shadows cast and support reflections on some surfaces. That’s still great, but keep those expectations in check for what ray tracing can and will be used for.

We know a bit about the ray tracing architectures used by Qualcomm and Arm, which gives us some insight into their capabilities. For starters, both speed up the core box and triangle crossings, which are the fundamental building blocks of ray tracing. Calculating these ray intersections in hardware is many times faster than in software.

However, only Qualcomm supports Bounding Volume Hierarchical (BVH) (we don’t know about Samsung’s Xclipse GPU), a technique similar to that used by Nvidia and AMD in their high-end GPUs. The BVH acceleration is important because it is used to speed up the computation of ray intersections by searching groups of polygons to narrow down the intersections, rather than casting each ray individually.

As such, we expect Qualcomm’s implementation to offer better frame rates and more ray tracing complexity, but that assumes its beam count crunching capabilities are primarily comparable to Arm’s. However, there are other aspects of ray tracing acceleration, such as: B. Noise reduction and memory management, which can also be fine-tuned to improve performance. We don’t know how far Arm or Qualcomm went in optimizing their wider GPU for these needs.

In numeric terms, Oppo claims a 5x boost for its PhysRay engine by switching from software to hardware acceleration with the 8 Gen 2. Meanwhile, Arm delivers a 3x boost in internal hardware versus software with its Immortalis G715 GPU -Benchmarking firm. Unfortunately, both metrics don’t tell us much about what kind of real-world performance and graphical capabilities we’re likely to see.

Qualcomm notes that it supports reflections, shadows and global illumination, key techniques for producing decent, if not super high-end, ray-traced effects. Likewise, Arm notes that it uses hybrid halftoning to enhance lighting, shadows, and reflections. However, layering these functions requires more and more processing power, and we don’t yet know how far the first smartphone chips can take the support and at what frame rate.

While we’ll have to wait and see what actual mobile games bring, it’s safe to say that a smartphone chip designed for a graphics power budget of less than 5W won’t match the performance levels of a gaming console or PC graphics card.

Nvidia’s latest RTX4080 graphics card, for example, is a 320W behemoth. At the same time, the Playstation 5 and Xbox Series X each consume around 200W (including their CPUs). 4K resolutions with all the bells and whistles just aren’t an option for smartphone ray tracing.

The best approximation of real-world performance comes from Oppo’s talk about its PhysRay engine during the Snapdragon Tech Summit Day One keynote. The company notes that it can hit 60 fps at a modest 720p resolution, which can be sustained for 30 minutes on the Snapdragon 8 Gen 2 platform. That sounds OK, but clearly highlights the compromises the phone has to make in terms of frame rate or resolution. Not to mention that sustained performance could also be an issue given the limited cooling available to the smartphone’s form factor.

Our time at the Snapdragon Summit also included a hands-on demo. Qualcomm presented a short animation that gave us the option to toggle ray tracing on and off. It was easy to tell the difference in lighting and reflections – even day and night. However, we couldn’t adjust the camera or move around the room, so there’s no way of knowing how well the performance will hold up.

Doom and Gloom aside, smaller smartphone displays don’t need ultra-high resolutions or ultra-high levels of graphic fidelity to look great. 720p 60fps or 1080p 30fps games with fancy lighting and reflections can still provide a remarkable boost in mobile graphics fidelity.

During their recent announcements, Mediatek and Qualcomm both noted that the first mobile game with ray tracing support will be released in the first half of 2023, just in time for phones to get into consumer hands. A game is hardly a drop in the bucket, and it will be a lot longer, possibly years, before ray tracing becomes mainstream for mobile.

That’s partly because games need to be profitable, meaning they’ll appeal to the mass market rather than just being made for a handful of phones. While there’s always free marketing for going first, ray tracing implementations will be an afterthought for many developers, at least until hardware gains wider adoption. It was the same with console and PC games. However, Mediatek notes that all major Chinese game studios are working to support ray tracing in the future. We’ve also spotted China’s Tencent and Netease Games on Qualcomm’s partner list, so some markets may transition to supporting the feature sooner than others.

Importantly, with Qualcomm on board, ray tracing is firmly on the map due to its sheer volume of sales. An increasing number of titles are likely to gradually sign up over the coming years, offering fancier reflections and lighting for the phones that support it. Ray tracing via the increasingly popular Vulkan API also means cross-platform ports are more viable than ever. So once again a lot to hope for in the longer term.

Hopefully this article has convinced you; no. You really shouldn’t rush to buy a new phone just because it supports ray-traced graphics. We haven’t even seen our first mobile game supporting this technology, so there should be no rush to be an early adopter here. To be honest, it might even be better to wait for second-gen ray-tracing GPUs to iron out the bugs and bump performance up a notch.

However, if you’re on the hunt for a new phone anytime soon and gaming is your top priority, it might well be worth waiting until 2023 to snag a phone that’s a little more future-proof. We expect the first telephone ray tracing announcement before the end of the year.

See also: The best gaming phones to buy today