In brief: No one really knows when you'll be able to get your hands on a Steam Deck, with shipping dates slipping into the second quarter of 2022. In the meantime, Valve and AMD are working to squeeze more performance out of the Zen 2 SoC inside the new handheld console, as well as improve its energy efficiency.
Valve's upcoming Steam Deck will be able to run Windows 11 for those who want it, but the majority of users will likely stick with the company's own Arch Linux-based SteamOS 3.0, which uses the Proton compatibility layer to run games that don't run natively on Linux.
A good reason to go with the default OS is performance, as Valve has been collaborating with AMD to develop an improved Linux CPU driver that will benefit not only the Steam Deck, but also many full-fledged PCs equipped with Zen 2 Ryzen CPUs and APUs. As we get closer to the official launch, the results of this effort are becoming clear and should lend more credibility to Valve's claims that its handheld console is capable of at least 30 frames per second in pretty much any recent AAA game.
The latest update on the matter comes via a presentation given by AMD's Ray Huang at the X.Org Developer's Conference (XDC 2021) earlier this month. According to Huang, the new AMD P-State driver leverages ACPI Collaborative Processor Performance Controls (CPPC) for better CPU frequency scaling and performance state switching decisions during various workloads. This will replace the existing ACPI CPUFreq driver, which is vintage at this point and isn't able to take advantage of AMD's modern CPU platforms, such as the semi-custom Zen 2 SoC inside the Steam Deck or Zen 3 processors and APUs for laptops and desktops.
Preliminary testing by AMD using an 8-core Ryzen 7 Pro 5750G APU reveals the new driver already enables performance-per-watt improvements of anywhere between 10 to 25 percent, or as much as 26.6 percent using the Gitsource Benchmark.
The company was also able to run Horizon Zero Dawn at 60 frames per second at 1080p with much lower power consumption than what was possible using the CPUFreq driver, which pegs the cores at 3800 MHz. By comparison, the P-State driver allows unused cores to go down to 400 MHz.
AMD is currently working to improve the stability of the new driver and getting it into the official Linux kernel, so we'll have to wait and see how it turns out when the Steam Deck becomes available for the general public. Valve began shipping developer kits last week, but people who pre-ordered the commercial version may not get one until Q2 2022.