SteamOS tested on dedicated GPUs: No, it’s not always faster than Windows

I wrote a couple of weeks ago about my personal homebrew Steam Machine, a self-built desktop under my TV featuring an AMD Ryzen 7 8700G processor and a Radeon 780M integrated GPU. I wouldn’t recommend making your own version of this build, especially with RAM prices as they currently are, but there are all kinds of inexpensive mini PCs on Amazon with the same GPU, and they’ll all be pretty good at playing the kinds of games that already run well on the less-powerful Steam Deck.

But this kind of hardware is an imperfect proxy for the Steam Machine that Valve plans to launch sometime next year—that box will include a dedicated GPU with 8GB of dedicated video memory, presenting both benefits and possible pitfalls compared to a system with an integrated GPU.

As a last pre-Steam Machine follow-up to our coverage so far, we’ve run tests on several games we test regularly in our GPU reviews to get a sense of how current versions of SteamOS stack up to Windows running on the same hardware. What we’ve found so far is basically the inverse of what we found when comparing handhelds: Windows usually has an edge on SteamOS’s performance, and sometimes that gap is quite large. And SteamOS also exacerbates problems with 8GB GPUs, hitting apparent RAM limits in more games and at lower resolutions compared to Windows.

Our testbed(s)

When we test GPUs, our goal is to have the best possible CPU, motherboard, and other components built around it so we can measure the graphics card’s performance without running into bottlenecks from anything else.

For this build, I tried a bit harder to replicate the kind of midrange components we can expect the Steam Machine to use in an attempt to control costs, though I had to work with the limits of what I had on hand—the 32GB DDR5 RAM kit is double what the Steam Machine will have, but none of the games we’re testing should have troubles running inside of 16GB. The 8-core Ryzen 7 7700X also has two more CPU cores than the Steam Machine will have and is running at a higher power limit, but it shares the same Zen 4 CPU architecture.

Our main goal was to test a range of dedicated GPUs to gauge how SteamOS would stack up against Windows. We did stick to all-AMD hardware here, though, because it gives us a better sense of how the Steam Machine itself might perform, and AMD CPUs and GPUs get the most attention from Valve since it’s what the company is actively supporting.

• A Radeon RX 7600 (32 RDNA3 CUs) with 8GB of RAM. This will give us the best idea of how the Steam Machine will actually perform, since Valve will be shipping an RDNA3 GPU with 28 CUs and the same amount of RAM.
• A Radeon RX 7600 XT (32 RDNA3 CUs) with 16GB of RAM. A higher-clocked version of the RX 7600, it should only perform 10 or 15 percent faster most of the time—except when games need more than 8GB of RAM. If a game is performing way better on the RX 7600 XT, it probably means the RX 7600 is running out of video memory, pointing to possible problems for the actual Steam Machine.
• A Radeon RX 6800 (60 RDNA2 CUs) with 16GB of RAM. A somewhat older card, but with the same RDNA2 architecture used in the actual Steam Deck. If SteamOS-vs-Windows numbers were different for this GPU than for any of the others, it could be because Valve has done more optimization work for this architecture than for newer versions.
• A Radeon RX 9070 (56 RDNA4 CUs, 220 W TBP) with 16GB of RAM. A newer card, thrown in to see how well SteamOS (and the open-source amdgpu Linux drivers) are doing with cards you could use if you wanted better performance at 4K.

All four of those GPUs were tested in the same system. For fun, we also threw in two PCs with integrated graphics:

• The high-end Framework Desktop, with its Ryzen AI Max+ 395 chip, Radeon RX 8060S GPU (40 RDNA3.5 CUs), and 128GB pool of unified LPDDR5X RAM. For $1,999, this is (hopefully!) a much more expensive box than the Steam Machine will end up being, but the basic $1,099 model is a decent alternative you can buy today, and this is as fast as integrated GPUs get.
• An Aoostar Maco mini PC from Amazon that I bought to play around with, using a Ryzen 7 H255 processor, 32GB of DDR5 RAM, and a Radeon 780M GPU. For a bit less than $500, this is one of the better values for the money you can get if you’re looking for a budget-ish Steam Machine with more power than the real Steam Deck.

The numbers

We run half a dozen built-in benchmarks across five games—they’re mostly a bit older, but they still represent a good mix of lighter and heavier games, both with ray-tracing effects on and off. And even in this relatively small number of games, not all of our data points in the same direction. But a few trends (and exceptions) do emerge.

The most noticeable, as we’ve covered elsewhere, is in games that hit the RX 7600’s 8GB RAM limit. Here, you see considerably larger gaps between Windows and SteamOS in some of the games we tested, most notably Returnal and Forza Horizon 5 at both 1440p and 1080p and Cyberpunk 2077 at 1440p with ray-tracing turned on. Returnal is the most noticeable example—the 16GB 7600 XT in SteamOS essentially ties with Windows, while Windows performs 60 or 70 percent faster on the 8GB RX 7600. The gap is smaller in most other games, but the 7600 does consistently struggle.

Other results vary from game to game and from GPU to GPU. Borderlands 3, for example, performs quite a bit better on Windows than on SteamOS across all of our tested GPUs, sometimes by as much as 20 or 30 percent (with smaller gaps here and there). As a game from 2019 with no ray-tracing effects, it still runs serviceably on SteamOS across the board, but it was the game we tested that favored Windows the most consistently.

Performance for Windows 11 25H2 vs. SteamOS 3.9 on the same hardware. In general, Windows edges out SteamOS on dedicated GPUs, even when VRAM isn’t a factor.

Performance for Windows 11 25H2 vs. SteamOS 3.9 on the same hardware. In general, Windows edges out SteamOS on dedicated GPUs, even when VRAM isn’t a factor.

Performance for Windows 11 25H2 vs. SteamOS 3.9 on the same hardware. In general, Windows edges out SteamOS on dedicated GPUs, even when VRAM isn’t a factor.

In both Forza Horizon 5 and Cyberpunk 2077, with ray-tracing effects enabled, you also see a consistent advantage for Windows across the 16GB dedicated GPUs, usually somewhere in the 15 to 20 percent range.

To Valve’s credit, there were also many games we tested where Windows and SteamOS performance was functionally tied. Cyberpunk without ray-tracing, Returnal when not hitting the 7600’s 8GB RAM limit, and Assassin’s Creed Valhalla were sometimes actually tied between Windows and SteamOS, or they differed by low-single-digit percentages that you could chalk up to the margin of error.

Now look at the results from the integrated GPUs, the Radeon 780M and RX 8060S. These are pretty different GPUs from one another—the 8060S has more than three times the compute units of the 780M, and it’s working with a higher-speed pool of soldered-down LPDDR5X-8000 rather than two poky DDR5-5600 SODIMMs.

But Borderlands aside, SteamOS actually did quite a bit better on these GPUs relative to Windows. In both Forza and Cyberpunk with ray-tracing enabled, SteamOS slightly beats Windows on the 780M, and mostly closes the performance gap on the 8060S. For the games where Windows and SteamOS essentially tied on the dedicated GPUs, SteamOS has a small but consistent lead over Windows in average frame rates.