Some windows games running on proton beat native windows performance. So yes.

Here’s a recent benchmark.

Edit: here’s the AMD GPU version if that’s what you’re using: https://youtu.be/D45AknAsIPw

Playing via Proton is absolutely fine! It's what is recommended actually!

I felt a compatibility module wouldn't offer nearly as good performance/efficiency as a game designed to run on Linux/ext4 - but are you saying that playing via Proton is fine?

Can confirm, it’s fine. There’s some variability of course but taken as a whole the environment is comparable in terms of performance. As long as you’re not playing AAA competitive games that have anti-cheat you are going to be fine with few exceptions. And there are plenty of examples where the proton experience works better than the native.

Check protondb to get a realistic idea of how well games will work.

You could check for yourself: https://www.protondb.com/

If a game is rated Gold or above, it's generally good to go on most systems. Platinum is the best rating other than Native, which means it's a game with an official Linux version. Proton is the reason I switched to Linux.

Bronze and Silver games might play fine too, but you'll either have to do some tinkering or it just won't work. It's not that often that these games work "out of the box."

Proton is just a compatibility layer, not a virtual machine or emulator. So while the specifics vary from game to game, in general, performance is comparable. In my experience it's just as stable and often faster than on windows (at least on AMD GPUs. But Nvidia has gotten better as well)

Absolutely. I play almost everything on steam deck these days, and proton gets fantastic performance results. It's not like the early days of wine, we're talking near-native or occasionally even better-than-native.

Proton isn’t an emulator; It’s a compatibility layer. All it’s doing is taking the Linux<>Windows stuff and converting back and forth. There’s very little efficiency loss, (and some games even run better because Linux tends to be a lighter OS.)

The big issue with Linux is anticheat. Some of the largest anticheat companies have chosen not to support Linux, or the game devs have disabled Linux support on their end. But to be clear, that’s not a choice Linux has made; It’s a choice the game devs made to exclude Linux players, because they want kernel-level control which Linux won’t allow.

Gaming on Linux used to be a big hassle, as it basically required devs to write a native Linux version of the game. But nowadays Proton does that translation for them, and is so lightweight that it’s negligible. If you have any doubts, check out protondb, which is a published list of game compatibility ratings. Gold will play just fine in 90% of cases. Platinum is going to be seamless. Native means there’s a specific Linux version. And Steam Deck Verified simply means the devs have set specific controller/aspect ratio/frame rate/etc settings for when the game is booted on a Steam Deck. Even if it’s not SD Verified, the rating will tell you whether or not the game will boot and run.

There is a setting under compatibility in Steam's preferences that allows all Windows games to install with Proton. Without it, Valve won't give you the download option unless they're 100% certain it will run perfectly. This excluded many games that run fairly well, and a bunch of games that run perfectly but haven't been properly assessed yet.