Valve held its Steam Deck Development Live Stream (opens in new tab) today where it revealed the inner workings of the Steam Deck. The company also shared more information on the custom SoC that AMD has cooked up to power the handheld gaming PC.
It should be common knowledge by now that AMD's Van Gogh APUs would combine the chipmaker's Zen 2 cores with RDNA 2 graphics. While some have hoped for an APU with Zen 3, that combination won't happen until next year when Rembrandt comes out. While we've always referred to the 7nm chips as Van Gogh, the specific SKU that Valve's putting inside the Steam Deck carries the "Aerith" codename. It's an SoC that AMD has built from the ground up to offer a steady performance during prolonged sessions, whether the Steam Deck is plugged in or not.
Aerith wields four cores and eight threads with clock speeds between 2.4 GHz and 3.5 GHz. We learned from the live stream that instead of shooting for high boost clocks, Valve focused more on offering consistent clocks. Even with its low clock speeds, Aerith shouldn't be frowned upon. The Zen 2 SoC delivers a peak FP32 (single-precision) performance up to 448 GFLOPs. It's not the most meaningful way to measure a processor's performance, but it was the only data that Valve provided. If you're looking for a comparison, Aerith should perform slightly slower than a Ryzen 3 Pro 4450U (473.6 GFLOPs), which is also a quad-core, eight-thread Zen 2 chip at 15W.
Aerith has a TDP that spans between 4W and 15W. However, Valve confirmed that there isn't a hard thermal limit on Aerith, and the company urges game developers to implement framerate limiters. Valve plans to enforce a framerate limiter in the near future in case developers don't put one inside their titles. The reason for not crippling Aerith from a thermal standpoint is that Valve's intentions were to have Aerith offer the same level of performance regardless of whether the device is in handheld or docked mode. In certain scenarios, such as when gaming outside on a hot day, the Steam Deck may cap the device's charge rates, download speeds, or SSD bandwidth to maintain the GPU performance.
On the graphics side, there are eight RDNA 2 compute units (CUs) that accompany the four Zen 2 cores. The CUs clock in between 1 GHz to 1.6 GHz. This is the same RDNA 2 engine that's found on AMD's latest Radeon graphics cards and comes with support for the same featureset, such as FidelityFX Super Resolution (FSR) and DirectX 12 Ultimate. On paper, the RDNA 2 unit pumps out up to 1.6 TFLOPs of FP32 performance. The performance is comparable to that of a GeForce MX450 (1.67 TFLOPs). Don't let the reference fool you, however, as early benchmarks have shown the Steam Deck hitting 60 FPS in many modern games with sensible graphics settings.
Valve paired Aerith with 16GB of LPDDR5 memory with 1GB of VRAM. Aerith is the first AMD mobile processor to leverage LPDDR5 memory. According to Valve, modern games are fine with 8GB or 12GB of memory, so the choice to go up to 16GB allows a bit of future-proofing on the Steam Deck. Furthermore, LPDDR5 memory is a great choice since AMD's APUs simply love bandwidth. That won't be an issue on the Steam Deck as LPDDR5 arrives bearing higher bandwidth, up to 88 GBps on Valve's upcoming handheld gaming PC.
The Steam Deck was originally scheduled to debut in December. However, the global supply chain issues have forced Valve to push it to a February 2022 release.