Half-Life: Alyx: Best vr_settings.ini for Low VRAM Graphics

While most settings are in the vr_settings.ini, the most critical VRAM overrides are actually handled via Steam Launch Options. This is because the Source 2 engine benchmarks your hardware at every boot and will overwrite the .ini unless forced.

File Path & Launch Strategy

• Config Path: [SteamLibrary]\steamapps\common\Half-Life Alyx\game\hlvr\cfg\vr_settings.ini
• Launch Options: Right-click Half-Life: Alyx in Steam > Properties > Launch Options.

Technical Note: In 2026, forcing a lower texture quality is the only way to play on 6GB cards without the “stutter-death” that occurs after 30 minutes of play.

Optimized “VRAM Recovery” Configuration Table

Parameter	Recommended Value	Technical Purpose
+vr_fidelity_level_auto	0	The Essential Fix. Disables the auto-resolution scaler that causes VRAM spikes.
+vr_fidelity_level	3	Locks the internal render scale to 100% (Native). Use 1 or 2 for ultra-low VRAM.
+vr_msaa	0	Disables Multi-Sample Anti-Aliasing to save ~$500\text{MB}$ of VRAM.
Textures (In-Game)	Low	Independently locks the texture pool size to prevent buffer overflow.
-nowindow	Added	Disables the desktop spectator window to save minor GPU overhead.

The Master “Low VRAM” Launch String

Copy and paste this into your Steam Launch Options to force the engine into a stable memory state:

-console -vconsole -nowindow +vr_fidelity_level_auto 0 +vr_fidelity_level 3 +vr_msaa 0 +vr_enable_volume_fog 0

HowTo: Engineering the VRAM-Safe Experience

Follow these GameEngineer.net technical steps to ensure 1% low stability:

1. The “Hidden” Texture Cog: Go to Settings > Performance and look for the small gear icon in the bottom-left. Many users miss this. Manually set Texture Quality to Low or Medium. Even on “Low Fidelity,” Alyx defaults textures to “High,” which consumes up to $7\text{GB}$ of VRAM alone.
2. Spectator Window Reduction: If you don’t use -nowindow, at least reduce the spectator resolution. Use the launch commands -w 1280 -h 720. This reduces the secondary frame buffer ($B_{sec}$) size on your GPU.
3. SteamVR Resolution Lock: Ensure your SteamVR “Per-App” resolution for Alyx is set to 100%. Because we disabled the game’s internal scaler (+vr_fidelity_level_auto 0), SteamVR’s setting is now the “Master” scale.
4. The Pagefile Buffer: On low VRAM systems, your Windows Pagefile acts as a safety net. Ensure your Pagefile is set to “System Managed” and is located on your fastest NVMe SSD. If it’s on an HDD, you will experience $2\text{–}3$ second freezes when VRAM swaps.
5. VRAM Audit: Use the console command +vr_perf_hud 1 to see your live memory usage. If the “Fidelity Level” is bouncing around, your launch options aren’t active.

Technical Explanation: Texture Pools and Swap Latency

The Source 2 engine uses a Virtual Texture Mapping ($VTM$) system. Instead of loading all textures at once, it keeps a “Pool” of active assets.

Mathematically, the VRAM requirement is: $VRAM_{total} = B_{render} + P_{texture} + B_{system}$.

When $VRAM_{total} > VRAM_{physical}$, the driver initiates a PCIe Bus Transfer ($T_{swap}$) to move data to System RAM. At 90Hz/120Hz, the latency of this transfer ($15\text{–}30\text{ms}$) is significantly higher than the frame budget ($8.3\text{–}11.1\text{ms}$). By forcing vr_msaa 0 and Texture: Low, you shrink $B_{render}$ and $P_{texture}$ enough to keep the entire working set inside the physical VRAM, eliminating the swap latency entirely.