Currently on the ROG Ally, you can only choose between two display resolutions; 1920x1080 and 1280x720. However, there are other 16:9 resolutions lower than 1080p that can result in higher performance in games with very little impact on visual fidelity, like 1600x900 for example. Here's how to enable these resolutions.
Step 0: Create a System Restore point in case something goes wrong.
Step 1: Download the latest version of the ROG Ally Custom Resolutions file.
Step 2: Double-click the downloaded file and click Run and Yes to the prompts.
Step 3: Restart Windows.
You should now have multiple display resolutions to choose from.
Benchmarks have shown that you can get anywhere between 16% to 44% better performance in games simply by switching to 1600x900 without loosing too much detail. Try it out.
I hope at some point Asus officially adds support for more resolutions so we don't have to do it via the registry. But until then, this is the way to go.
Kudos to Discord user AllyPal for the mod and Filterless for the benchmarks.
