Ryujinx: Best system.json for Zelda: Tears of the Kingdom 4K

The objective is to utilize the “Extra DRAM” ($8GB$) simulation to prevent the memory leaks that often occur during long play sessions in the Depths or when using Ultrahand.

1. Modifying the system.json for 8GB DRAM

By default, Ryujinx simulates the Switch’s 4GB of RAM. For 4K assets and high-resolution texture mods, this creates a bottleneck.

File Path: %AppData%\Ryujinx\system.json (or your portable folder)

Technical Overrides:

{
  "system_region": "USA",
  "system_language": "English",
  "enable_vsq": true,
  "expand_dram_size": true,
  "enable_multicore_scheduling": true,
  "ignore_missing_services": true
}

• expand_dram_size: Setting this to true (equivalent to the 8GB toggle in GUI) allows the emulator to buffer more high-resolution 4K textures, drastically reducing the “Asset Pop-in” latency.

2. Graphics Configuration for 4K Stability

While system.json handles the backend, the GUI must be tuned to prevent SPU-to-GPU desync.

Setting	Recommended Value	Technical Purpose
Graphics Backend	Vulkan	Best performance for modern NVIDIA/AMD drivers in 2026.
Resolution Scale	3x (4K)	Internal Resolution (IR) scaling. $3 \times 720p$ provides a crisp 4K output.
Post-Processing	None (or FSR)	If using native 4K, set to “None” to avoid double-processing lag.
Shader Cache	Enabled	Critical: Prevents stuttering during ability usage.
Macro HLE	Enabled	Improves GPU performance by high-level emulating common GPU commands.

3. The “TOTK Optimizer” Integration

In 2026, manual .json editing is often combined with the TOTK Optimizer tool. This tool creates a custom patch that synchronizes your system.json settings with the game’s internal dynamic resolution engine.

• Shadow Resolution: Set to 1024 or 2048 within the optimizer.
• LOD Quality: Set to Ultra to take advantage of your NVMe Gen 5 bandwidth ($B_{disk}$).
• FPS Target: Set to 60 (Ensure vsync is Enabled in Ryujinx to avoid physics speed-up glitches).

4. Troubleshooting: “Texture Exploding” at 4K

If you see geometric spikes or textures stretching to infinity:

1. Navigate to Settings > Graphics.
2. Enable “Texture Recompression”. This reduces VRAM usage by up to 25% ($V_{usage}$), which is vital when running at 4K IR.
3. Ensure your Anisotropic Filtering is set to 16x manually in the emulator, not forced via the GPU control panel.