Valve provides a deep dive into Steam Deck’s custom hardware design

Valve’s full, hour-long, developer-centric presentation.

Valve’s Steam Deck portable hardware may be delayed for a couple of months, but that didn’t stop Valve from discussing a lot of interesting details about the system during a powerful developer-centric livestream Friday. That included a lot of talks on hardware specs and software interpolation, but also design decisions on how to balance concerns about hardware power and battery power. AMD’s custom Steam Deck APU, nicknamed Aerith after the Final Fantasy VII character, is the core of the system and was the focus of the presentation. AMD says the system is the company’s first mobile chip to feature a RDNA2 GPU architecture, so it should have full support for DirectX 12 and the latest Vulkan APIs. That also means that the Steam Deck will not only be compatible with the entire Steam library, but many Steam games will already be. optimized for the specific chip configuration found inside, Valve says.

The CPU portion of the Aerith chip features four Zen 2 cores capable of running eight threads at 3.5 Ghz. Meanwhile, the GPU features eight RDNA2 compute units running at 1.6 Ghz.

While most Steam games these days get by with just 8 or 12GB of RAM, Valve said it chose to put 16GB of RAM LPDDR5 on Steam Deck because “we want to make sure that the Steam Deck is not only compatible with current games, but can also run games that have not yet been released.” A minimum of 1GB of that RAM is dedicated to the GPU, but the Steam Deck’s unified architecture means the GPU can access up to 8GB depending on what’s happening in the game or even exceed that “game-to-game” limit. RAM’s 128-bit wide bus also allows for 88 Gbps of total memory bandwidth, or 55 GB / s / TFLOP, which Valve says beats some desktop GPUs.

When it comes to storage, Valve said its tests showed little difference in real-world load time between eMMC drives (on low-end Steam Deck models), NVMe SSDs (on high-end models), and the built-in SD. card reader. Despite the vastly different bandwidth speeds for each option, boot times differed by 25 percent or less from each other in Valve’s early tests (although the company said the tests are currently far from complete) .

Drinking battery

Valve spent a lot of time talking about how the vapor rig was optimized for battery life, specifically designed to fit into a small power envelope in the 4-15W range. LPDDR5 RAM is useful there too, with no shortage of power. Power-saving features that come into play in low-stress scenarios like 2D games and idle / idle modes. That means a suspended Steam Deck should last “hours or even days” without needing to be plugged in, Valve said.

However, when connected via USB-C, the Deck can draw 45W of power, enough to charge at full speed and power a game at the same time. Steam Deck can also provide 7.5W of power to plugged-in peripherals, enough to power webcams, wired controllers, or external storage devices. For wireless accessories, Bluetooth 5.0 means that the Steam Deck can support wireless headsets and “multiple controllers” at the same time. You can also change to Bluetooth low energy mode for less intensive use cases.

Valve says it wanted to make sure its APU delivered consistent performance rather than relying on “turbo boost” or other modes that can temporarily increase hardware power (and power consumption) in laptops and phones. A game on the Steam Deck should perform identically within the first ten seconds and after hours of continuous use, Valve said, and the performance of the game on the Steam Deck should be consistent, whether it’s plugged in, on battery, docked, charging or discharging. games. Even moderately high ambient temperatures shouldn’t affect performance, Valve said, although if things get too hot outside, the system can throttle battery charge rates, discharge speeds, and even SSD speeds to maintain the GPU. running as consistently as possible.

Since the APU does not have strict limits on its power consumption, Valve says that games running on the Steam Deck should enforce a frames per second limit of 60 fps (to match the screen) or 30 fps (for games that push the GPU) to maintain battery life. That frame rate cap also helps contribute to the Steam Deck’s battery life in many games, AMD said. If a game processes a frame faster than the 16.66 milliseconds required for the 60fps frame rate, the APU will instantly switch to very low power mode until the frame is displayed, then go back to full power to calculate the next frame .

Valve says it is working on a global fps limiter to enforce the 30/60 fps guidelines in all games running on the Steam Deck. Developers will also have access to “extra buttons” to help adjust the balance between performance and battery life.

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