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Minecraft 26.2 Fabric VRAM optimization mod — Reduce GPU memory without touching shaders or resource packs.
I originally wanted to make an optimization mod for my low-end AMD GPU because I noticed unstable frame rates. I couldn't do much about it, but with the help of AI I was able to bring my ideas to life.
However, as development progressed, I discovered that VRAM was actually the bottleneck. So I changed direction and created this mod optimized for low VRAM environments.
This mod is theoretically universal across GPU vendors.
For users with GPUs that have 4GB or 6GB of video memory, this can reduce stuttering caused by insufficient video memory.
The mod is under active development. If you don't see any files on the download page, it means it's still under review or undergoing bug fixes. The mod is currently in beta.
After updating to the latest AMD GPU driver(26.6.4), VRAM usage became more normal.
Therefore, this mod will have to wait until the Vulkan API is released to see what else it can do.
VRAM Tweak intercepts GPU texture creation at the Blaze3D engine level via Mixin injection. It caps oversized texture atlases, downscales depth buffers, limits animation frames, and dynamically adjusts render distance when VRAM runs low — all without modifying Sodium, Iris, or any third-party mod code.
| Feature | How It Works | Triggered In Testing |
|---|---|---|
| Atlas Size Cap | GpuDevice.createTexture() W/H clamped to maxAtlasSize |
✅ 26 caps/session (blocks.png 16384→4096) |
| Depth Downscale | D32_FLOAT → D16_UNORM shadow maps | ✅ 10×/session, ~50% VRAM per shadow map |
| Format Downscale | RGBA16F → RGBA8 color buffers | |
| Shadow Map Cap | Clamp shadow map resolution ≤ shadowMapMaxSize |
|
| Animation Limit | Cap animated texture frame count | ✅ Stable |
| Particle Limit | Global particle count safety net | ✅ Experimental |
| VRAM Governor | Auto-lower render distance under VRAM pressure | ✅ Experimental |
| Budget Tracking | Per-frame VRAM polling + configurable alert | ✅ Stable |
⚠️ Important: Toggling the mod ON/OFF via GUI takes effect immediately for new textures only. Textures already loaded into VRAM stay at their current size until you restart the game. If you disable the mod and VRAM usage doesn't increase, this is expected — restart to reload textures at full resolution.
Real-time performance overlay with independent toggles for each metric:
| Toggle | What It Shows |
|---|---|
| FPS (Smooth) | 0.5s rolling-window frame rate |
| FPS (Average) | 5s sliding-window mean |
| 1% Low FPS | Slowest 1% of frames — perceived smoothness |
| 0.1% Low FPS | Worst 0.1% — stutter detection |
| Frame Time | Average milliseconds per frame |
| VRAM | Used / Total + percentage (color-coded) |
| Atlas Stats | Texture atlases tracked vs. size-capped |
| Allocations | GPU texture alloc/free counters |
| Downscales | Depth & format downscale trigger counts |
| Budget | Warning status + peak VRAM % |
Configure via Cloth Config GUI or config/vram-tweak.json.
/vramtweak stats — Print current VRAM + FPS stats to chat
/vramtweak dump — Write a full diagnostic report to disk
/vramtweak hud — Toggle HUD overlay on/off
/vramtweak benchmark — Quick VRAM stress test
Hardware: AMD R5 5600 + 32GB DDR4 + RX 6650 XT 8GB
Software: MC 26.2 + Sodium + Iris + resource pack + shaders
For a comparison, please refer to this: Comparison Document
| Metric | Before | After | Savings |
|---|---|---|---|
| VRAM Peak | 7820 / 8192 MB (95.4%) | 4728 / 8192 MB (57.7%) | ~3 GB |
| Stability | Stuttering near VRAM limit | 0 budget warnings | Smooth & playable |
26 oversize caps in one session:
| Atlas | Original | Capped | Savings |
|---|---|---|---|
blocks.png |
16384×8192 | 4096×4096 | ~240 MB |
armor_trims.png |
16384×8192 | 4096×4096 | ~240 MB |
items.png |
8192×4096 | 4096×4096 | ~64 MB |
Total: Atlas caps + depth downscales → ~2.5 GB VRAM saved. Usage dropped from 95.4% to 57.7%.
| Dependency | Type | Version |
|---|---|---|
| Sodium | Suggested | 0.9.0+ |
| Iris | Soft | 1.11+ (shader compatibility) |
| Cloth Config | Soft | 26.2+ (GUI) |
| ModMenu | Soft | 20.0+ (config button) |
Platform: Windows, Linux
Java: 25+
Compatibility: Tested with Iris + C2ME + Lithium + resource packs + shaders.
| GPU Vendor | Auto-Detect | VRAM Tracking |
|---|---|---|
| AMD | ✅ GL_VENDOR |
✅ GL_ATI_meminfo (KB-precise) |
| NVIDIA | ✅ GL_VENDOR |
✅ GL_NVX_gpu_memory_info (KB-precise) |
| Intel | ✅ GL_VENDOR |
❌ No dedicated VRAM (iGPU uses system RAM). Safe — automatically skipped. |
- Install Fabric for Minecraft 26.2
- Install Sodium
For 26.2 , If you install Iris, Sodium must be version 0.9.0, because Iris is not compatible with versions higher than 0.9.0. For 1.21.11 , Sodium must be version 0.8.13-beta-1, because Iris is not compatible with versions higher than 0.8.13-beta-1.If you don't use Iris, there may be no restrictions. - Install Cloth Config API
- Install Iris
this is optional - Drop
vram-tweak-x.x.x.jarintomods/ - Launch — Open Mod Menu → VRAM Tweak → Enable features
All settings live in config/vram-tweak.json. Use Cloth Config GUI (Mod Menu → VRAM Tweak) for interactive setup.
git clone <repo-url>
cd Minecraft-AMD-GPU-Tweak
./gradlew build
# Output: build/libs/vram-tweak-x.x.x.jarRequires JDK 25+ and Gradle 9.6+.
Mixin Injection Layer
├── MixinGpuDevice_VRAMOptimize → createTexture() format/size cap
├── MixinGameRenderer_Metrics → Per-frame stats + VRAM polling
├── MixinGameRenderer_CAS → FSR CAS sharpening pass
├── MixinSpriteContents_Animation → Animation frame capping
├── MixinParticleEngine_Cap → Global particle limit
├── MixinOptions_RenderDistance → VRAM Governor hook
├── MixinGui_Hud → HUD overlay rendering
└── MixinMinecraft_Hud → HUD data collection
Core Modules (src/main)
├── VRAMOptimizer → Format/size policy engine
├── VRAMGovernor → Dynamic render distance controller
├── MetricsEngine → Ring-buffer performance sampling
├── VramFrameCounter → Sliding-window FPS + percentile lows
├── VerificationLogger → Before/after audit trail
├── GPUDetector → Vendor detection + VRAM query
└── VRAMConfig → Gson-based config with 7 sections
Client Modules (src/client)
├── CasShader → GLSL CAS fullscreen post-process pass
├── VramTweakHud → Singleton overlay renderer
├── VramTweakCommand → /vramtweak CLI
├── ClothConfigFactory → GUI integration
└── ModMenuIntegration → Mod Menu entry point
Creative Commons Legal Code — See LICENSE.
{ "vram": { "enabled": true, // Master VRAM switch "shadowMapMaxSize": 1024, // Shadow map resolution cap "formatDownscale": false, // RGBA16F→RGBA8 "depthDownscale": false, // D32→D16 "budgetTracking": false, // VRAM usage monitor "budgetWarningPercent": 80 // Warn above this % }, "texture": { "animationLimit": false, "maxAnimationFrames": 32, "atlasSizeLimit": false, // Cap texture atlas size "maxAtlasSize": 4096 }, "governor": { "enabled": false, // Dynamic render distance "hysteresis": 10, "minDistance": 4, "cooldownTicks": 100 }, "particle": { "enabled": false, "maxParticles": 2000 }, "hud": { "enabled": true, "showFps": true, "showFpsAvg": true, "showFps1Percent": false, "showFps01Percent": false, "showFrameTime": true, "showVram": true // ... more toggles }, "cas": { // 🆕 FSR CAS sharpening "enabled": false, "sharpness": 0.8 } }