SteamOS 3.8 Runs Smoothly on ASUS ROG Xbox Ally X Handheld – Performance, Battery Life and Customization

Introduction

The ASUS ROG Xbox Ally X, a high‑end handheld gaming PC powered by AMD’s Z2 Extreme APU, has long been a curiosity for Linux enthusiasts. While the device runs Windows flawlessly, getting the official SteamOS 3.8 to boot proved challenging on earlier firmware versions. With the latest main‑line release, the OS now starts without issue, opening the door to a fully Linux‑based handheld experience. This article explores the installation process, system tweaks, performance across a range of titles, and battery life compared to Valve’s Steam Deck.

Getting SteamOS 3.8 on the ROG Xbox Ally X

Compatibility and Boot Issues

Earlier attempts to install SteamOS on the Ally X failed on the Z2 Extreme and other Ryzen AI chipsets (e.g., Strix Point, Strix Halo). The new 3.8 branch resolves these boot problems, allowing a clean installation directly onto the device’s internal storage.

Core Functionality

After flashing, the following components work out‑of‑the‑box:

• Wi‑Fi and Bluetooth connectivity
• 120 Hz variable‑refresh display
• Standard Steam Deck UI with full controller support

The only notable omission is RGB lighting control, which intermittently powers off and cannot be managed through the current SteamOS version. A simple reboot restores it, but the feature remains unsupported.

System Specifications and TDP Management

Hardware Overview

• CPU/GPU: AMD Ryzen AI Z2 Max, up to 5 GHz, 8 cores / 16 threads
• iGPU: Radeon 890M, 16 compute units (CU)
• Memory: 24 GB total – 13.24 GB system RAM, 10 GB allocated to VRAM
• Battery: 80 Wh, larger than the Steam Deck’s 40 Wh cell

TDP Control via Third‑Party Plugins

SteamOS does not expose native TDP sliders. The community‑maintained Decky Loader plugin Simple Decky TDP adds this functionality, offering:

• Adjustable power envelope from 4 W to 40 W
• Options to prioritize GPU or CPU performance
• Seamless integration with the SteamOS performance overlay

These controls are essential for balancing performance against battery life on a handheld platform.

Customization Options

Using CSS Loader, users can replace the default Steam Deck theme with personalized styles, altering UI colors, fonts, and layout. Additional tweaks include:

• Hiding the on‑screen overlay
• Disabling the frame limiter for higher refresh rates (up to 120 Hz)
• Configuring FSR (FidelityFX Super Resolution) and scaling filters

All changes are applied without leaving the SteamOS environment, preserving the native experience.

Performance Benchmarks

Methodology

Benchmarks were run at a consistent 720p resolution with the Steam Deck preset (low settings for most titles). Power draw was locked using the Simple Decky TDP plugin to match the Steam Deck’s maximum 15 W envelope for direct comparison.

Steam Deck vs. ROG Xbox Ally X at 15 W

Game	Steam Deck OLED (15 W)	ROG Xbox Ally X (15 W)
Shadow of the Tomb Raider (low)	72 FPS	80 FPS
Cyberpunk 2077 (low)	44 FPS (up to 47 FPS)	58 FPS

The Ally X consistently outperformed the Deck at the same power budget, thanks to the more powerful APU and higher memory bandwidth.

High‑Power Scenarios (30‑35 W)

When the TDP limit is raised, the Ally X demonstrates its true potential:

• Borderlands 4 – 900p low with FSR, 35 W TDP; frame rate hovers just below 60 FPS, limited by current game optimizations for iGPUs.
• Cyberpunk 2077 – 1080p high, 25 W TDP; average 52 FPS. Dropping to 900p medium at 20 W yields ~64 FPS.
• Spider‑Man 2 – 1080p medium with FSR frame generation; frame gen is essential to breach the 60 FPS threshold on this iGPU.
• Elden Ring – 1080p medium, 30 W TDP; average ~58 FPS, indicating the game’s CPU‑heavy nature.
• Doom: The Dark Ages – 900p medium, 30 W TDP, balanced FSR; ~63 FPS without frame generation.

Overall, the Ally X can sustain 30‑35 W for demanding AAA titles while staying near or above 60 FPS, a capability the Steam Deck cannot match due to its hardware ceiling.

Battery Life Comparison

All tests used a screen brightness of 50 % and a system‑wide refresh rate of 60 Hz.

• Indie/2D Gaming (8 W draw): ~10 hours of runtime on the 80 Wh battery.
• AAA Gaming at 17 W TDP: ~3 hours (total draw ~26 W).
• AAA Gaming at 25 W TDP: ~2.5 hours (total draw ~31 W).

For reference, the Steam Deck OLED draws about 8 W in a similar indie scenario, but its smaller 40 Wh battery yields roughly half the runtime. Even with the RGB lighting still active (which cannot be disabled), the Ally X demonstrates respectable endurance, especially considering its larger screen and higher performance envelope.

Conclusion

The successful launch of SteamOS 3.8 on the ROG Xbox Ally X marks a significant milestone for Linux handheld gaming. Despite the lack of native RGB control, the device offers:

• Full Wi‑Fi, Bluetooth, and display functionality
• Robust TDP management via community plugins
• Deep UI customization through CSS tweaks
• Superior performance to the Steam Deck at equivalent power levels
• Competitive battery life thanks to an 80 Wh cell

While some games still suffer from iGPU‑related optimizations, the Ally X proves that a high‑end handheld can deliver a compelling SteamOS experience without sacrificing portability. Users can choose a pure Linux setup, a dual‑boot configuration, or retain Windows for broader compatibility—giving flexibility that rivals the Steam Deck’s more limited hardware.

Future driver updates and game‑specific optimizations are likely to close the remaining performance gaps, making the ROG Xbox Ally X an increasingly attractive option for gamers seeking a premium handheld Linux platform.