PS5 Pro GPU explained by architect Mark Cerny: Hybrid GPU with multi-generational RDNA tech

PlayStation console architect Mark Cerny breaks down the granular details of the PS5 Pro's GPU in a new in-depth video.

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Today Sony surprise dropped a 37-minute technical seminar with Mark Cerny aimed at clarifying some the PS5 Pro's new magical upscaling sorcery. In the video, Cerny discussed the PS5 Pro's GPU in length, confirming the processor is built on multi-generational RDNA tech from AMD--alongside a custom ML solution.

Sony splashed parts of AMD's RDNA 2 and 3 architectures into the Pro's GPU, a combination referred to as RDNA 2.x, but had to be selective to ensure Pro games were still compatible with the base PS5 (which runs on RDNA 2.0). Cerny gives examples of RDNA 3 usage with the Pro's boosted primitive processing capabilities.

Below we have transcriptions along with images from the video:

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This is what we used in the PS5, it's a GPU from our partner AMD. More specifically, it was an RDNA 2 GPU, meaning it used the second generation of RDNA 2 technology. The GPU has sub-units called Work Group Processors (WGP). PlayStation 5 has 18 of them.

The GPU on the PlayStation 5 Pro is much larger. It has 30 Work Group Processors. It's also what I'm calling a hybrid RDNA GPU, which is to say that it combines multiple generations of RDNA technology.

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The base technology for PS5 Pro is somewhere between RDNA 2 and RDNA 3. I'm calling it RDNA 2.x. As I'll shortly explain, that choice makes it much easier for game developers to port their games to the new console.

Raytracing uses what I'm calling future RDNA technology. It's roadmap RDNA that's well past the feature set today. It's showing up here first.

And machine learning is custom, or to be more specific, it's custom enhancements to RDNA. And just to be clear, I may say machine learning or ML, or AI today, these are just different words for the same topics.

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To support that GPU, we needed faster memory and more memory. The faster memory was pretty simple. The system memory on PS5 Pro has bandwidth of 576GB/sec, which is 28% higher than PlayStation 5.

Cerny goes on to explain the discrepancy between the PS5 Pro's TFLOPs figure, namely the erroneous 33TFLOPs number that had been passed around.

You may have seen that the PS5 Pro is either 16.7 TFLOPs or 33TFLOPs, depending on where you look. Which is it? The Pro actually has 16.7 TFLOPs of power, or about a 67% increase over the base PS5.

So where did the 33TFLOPs number come in? It turns out that this was based on speculation rooted in some fact. AMD's newer RDNA 3 GPU tech effectively double TFLOPs of RDNA 2, and since the PS5 Pro was believed to use an RDNA 3 GPU, the Pro's TFLOPs were also doubled in the configurations.

As it turns out, Sony couldn't count the Pro's TFLOPs in that way because it would effectively create a new generation and require developers to release two separate versions of their games--a PS5 version, and a version specifically built for the PS5 Pro.

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"Achieving that bonus in performance would require a recompile for PS5 Pro, and as I said, having two versions of games would create more work than we're comfortable asking the developers to do."

As for the correct math, Cerney explains:

"Here then is the correct math, and it's pretty simple. PS5 Pro has 30 Work Group Processors, which is 67% more than the PS5 has, so the FLOPs should be 67% higher as well. If we assume a pretty common operating frequency of 2.17 GHz, the math works out to 16.7 TFLOPs on PS5 Pro."