Most of the GPUs in the hot new PlayStation 5 Pro are fairly old technology. However, we can preview the ray-tracing upgrades that will be made possible by AMD's new RDNA 4 graphics chip for PC gamers.

This is from the same PS5 Pro deep dive that also revealed Sony's own take on the console's AI hardware rather than using AMD's technology.

Mark Cerny, lead architect of Sony's PlayStation console, explained that the PS5 Pro's GPU is RDNA 2-based, just like the original PS5. The reason for this is simple: compatibility.

By largely inheriting RDNA 2 technology in the shaders of the PS5 Pro's GPU, game developers only need to compile a single code path to run on both PS5 and PS5 Pro.

However, the PS5 Pro is not identical. The base technology for the PS5 Pro is something between RDNA 2 and RDNA 3.” For starters, the shaders are RDNA 2, but parts of the geometry pipeline are from RDNA 3

. The same code can be used on both consoles, but it simply works better on the PS5 Pro.

However, if Sony had used a method that doubled the floating point capability of RDNA 3, it would have required compiling two code paths, one for the PS5 and one for the PS5 Pro. Sony did not want to burden game developers with a new generation of consoles, but with a mid-life refresh.

From a PC gaming perspective, however, the most intriguing aspect of the PS5 Pro's GPU is the ray tracing; according to Cerny, the upgraded ray tracing hardware was sourced from the “future RDNA” generation.

Cerny was not specific, but it is clear that this technology will “first appear” on the PS5 Pro and is not currently on any other AMD chip, given that RDNA 4 is expected to replace the architecture-branded CDNA, only RDNA 4 will remain

. For more details, please see the video. But the short version is that it doubles the performance of BVH and adds new stack management hardware.

The BVH performance enhancements will improve ray tracing performance broadly, and the new stack management engine will be especially useful for complex reflections.

So how does this affect performance?

“We've seen a lot of rays being computed at two to three times the speed of Playstation 5,” says Cerny, “but we've also seen rays being computed at two to three times the speed of Playstation 5.

However, this performance increase also includes the simple effect of the PS5 Pro's GPU being 67% larger and more complex than the PS5; Cerny estimates that this alone tends to improve real-world performance by about 45%.

In other words, given that Sony claims that ray tracing will typically be 100% to 200% faster on the PS5 Pro, it is clear that most of this improvement is due to the architecture, not simply the result of 67% more functional units being added.

This bodes quite well for RDNA 4 GPUs. Currently, AMD's ray-tracing performance is among the lowest of the three major GPU vendors for PCs.

Intel's new B580 GPU has a fairly decent ray tracing throughput, but it is Nvidia that is leading; based on the improved ray tracing in the PS5 Pro, AMD is probably in the lead with Nvidia, if not all, It is expected that they will close most of it. [Of course, Nvidia will be launching its own new GPU architecture early in the new year alongside AMD's RDNA 4. That would put AMD at a distinct disadvantage.

However, we hope that the ray tracing in RDNA 4 has been sufficiently improved to make it easier to use than that of existing RDNA 2 and RDNA graphics cards for PCs. Please note this point.