Current SteamOS is mainly for the Steam Deck. Wider deployment is still WIP.

It's not too difficult to install a general Linux distro and do all the Steam and Proton setup yourself.

Bazzite is popular right now for pre-configuring most of it.

Cause they dropped support for Steam OS 2.x

Wait for Desktop release of Steam OS 3.x

引用自 Rekcuf Nmad：

“The Alpha cannot support Windows 11. That leaves running Linux”

This is untrue, to a certain extent. You can install Windows 11 on any old board like this R1 Steam Machine by Alienware using a software called Rufus (or others like it) bypassing TPM checks and allowing the old hardware to run windows 11. It’s completely free and easy to try and do, and I suggest looking it up, but I wouldn’t use this an an excuse to not download windows 11 on the steam machine.

Valve stopped supporting SteamOS 2 a long time ago and it's been End-of-Life for several years. They removed the old Steam OS 2 pages from the Steam Universe and redirected the SteamOS downloads page to the Steam Deck recovery images shortly after the Steam Deck launched.

For now, either wait for Valve to finish SteamOS 3 for general availability (who knows how long that will be) or install something like Bazzite. I'd do the latter and install Bazzite on it.

In regards to how well some of those other features like the HDMI passthrough work is another matter as that may not work properly.

Lastly, you can also now at least try SteamOS 3 proper by trying to use the Steam Deck recovery image. Since they added support for the Legion GO S / 3rd party handhelds Valve removed the device ID checks from their install script. It's very hit or miss depending on the hardware in the system so just understand it may not be smooth sailing if you try this. Also you'll need to understand how the image based installation works; especially if you have more than one disk installed in the system.

引用自 thesixthgoat：

引用自 Rekcuf Nmad：

“The Alpha cannot support Windows 11. That leaves running Linux”

This is untrue, to a certain extent. You can install Windows 11 on any old board like this R1 Steam Machine by Alienware using a software called Rufus (or others like it) bypassing TPM checks and allowing the old hardware to run windows 11. It’s completely free and easy to try and do, and I suggest looking it up, but I wouldn’t use this an an excuse to not download windows 11 on the steam machine.

Linux is still better for it given the specs with virtually zero room for hardware changes due to the form factor of the Alpha R1. It's true that it can by bypassing requirements, but it's a pointless endeavour because of how terrible the OS is.

We're talking about a system that shipped with either an i3-4130T, i5-4765T, or i7-4790T, with a GTX 860M-based GPU, and up to just 8GB DDR3. Windows 11 was intended for much newer hardware even if you can bypass the requirements, the OS is bloated and won't run as well on older hardware, especially if the OP's model shipped with the i3 or i5 because you're working with only 4 threads in both instances.

Linux distributions that aren't too heavy on RAM like Mint would waste far fewer CPU and RAM resources, allowing for less hiccups compared to 11, even if the average FPS might be a bit lower on average, at least it's stable because you aren't pegging 100% usage just from opening a Chromium browser.

引用自 Rekcuf Nmad：

Hello,

I own an Alienware Alpha R1. As you may already know the Alpha R1 is also a Steam Machine. I am unable to locate the version or ISO for my particular Device. I was wondering if it was still available, as I will soon by replacing my Alpha with a new PC due to Microsoft no longer supporting Windows 10 after October this year. The Alpha cannot support Windows 11. That leaves running Linux, and I would love to continue to be able to use a machine that I've have for the past decade or so alive and using some features such as the HDMI Passthrough.

All the links I am finding for Steam OS seem to be Steam Deck recovery which, to the last of my knowledge, is not ready for non-steam deck devices.

SteamOS from your machine's time period was completely different. SteamOS 1 and 2 were based on Debian and have been deprecated for years, whereas SteamOS 3 (for the Steam Deck) is based on Arch and is the only variation actually available, but presently not ready for the majority of computers and devices. One of the reasons for this is issues Valve's had with NVIDIA drivers, among other problems, since SteamOS 3 was made specifically for the Steam Deck's hardware, and they're trying to guarantee quality across the board.

You're better off trying another distribution while you wait, i.e. Linux Mint, Bazzite (using legacy drivers), etc.

I have windows 11 running on my Alienware Alpha R1 i have the i7 version