TurboQuant+ Config-I quantization of google/gemma-4-31b-it. Config-I applies WHT-domain compression (TQ4_1S) to attention and gate/up tensors while keeping boundary layers and ffn_down at higher precision for optimal quality. See the getting started guide for details.

Requires TurboQuant+ llama.cpp fork at tag tqp-v0.1.0. Will NOT work with stock llama.cpp. TurboQuant+ is an independent research project. These quantization types have not been merged into upstream ggml-org/llama.cpp. Do not file issues there for TQ models.

Files

File	Quant	Size	vs Q8_0	KLD vs Q8_0	KLD vs Q4_K_M
Gemma-4-31B-it-Config-I.gguf	Config-I	18.9 GB	62% of Q8_0 (30.4 GB)	0.125	5% better

Why Config-I over Q4_K_M?

Config-I is ~8% larger than Q4_K_M but delivers measurably better quality — closer to Q8_0 output than Q4_K_M on every metric.

Quant	Size	Median KLD	Same top token
Q8_0	30.4 GB	baseline	baseline
Q4_K_M	17.4 GB	0.132	74.2%
Config-I	18.9 GB	0.125	74.9%

Lower KLD = closer to Q8_0 output. Higher same-top-token = more likely to pick the same word as the unquantized model.

Note: Standard wikitext PPL produces invalid numbers on Gemma 4 due to tokenizer differences. KL-divergence against Q8_0 logits is used instead, which directly measures how much quantization changes model outputs.

Compatibility

Field	Value
Fork	TheTom/llama-cpp-turboquant
Tag	`tqp-v0.1.0`
Backends	Metal, CUDA, ROCm/HIP, Vulkan
Quantized on	2026-04-08

No forward-compatibility guarantee. This model was built and validated against the tag above. Future fork updates may change the format. If decode produces garbage, rebuild from this tag.

Benchmarks (Apple M5 Max 128GB, Metal)

Speed

On Metal, Config-I trades decode speed for better quality at lower memory. CUDA performance has not been validated on this model yet. Based on other TQ4_1S results, performance is expected to be higher than Metal.

Metal (Apple M5 Max 128GB, recommended -ctk q8_0 -ctv turbo4)

Config	pp512	pp2048	tg128	Size
Q8_0 baseline (f16 KV)	488 t/s	389 t/s	15.5 t/s	30.4 GB
Q4_K_M (f16 KV)	468 t/s	—	24.4 t/s	17.4 GB
Config-I + turbo4 KV	356 t/s	310 t/s	9.6 t/s	18.9 GB + KV cache memory reduction

Config-I is ~2.5x slower decode than Q4_K_M on Metal (9.6 vs 24.4 t/s). The value here is quality, not speed. If you need maximum throughput, use Q4_K_M. If you need the best quality that fits in memory, use Config-I.

Context Scaling (tg128 decode at varying context length, Metal)

Context	1K	4K	8K	16K	32K
t/s	9.8	9.4	9.6	9.6	9.7

Effectively flat decode performance across all context lengths. No degradation cliff.

Quality (KL-divergence vs Q8_0, wikitext-2-raw, 512 context, 5 chunks)

Config	Median KLD	Same top token
Q4_K_M	0.132	74.2%
Config-I	0.125	74.9%

Recommended KV Cache Settings

TurboQuant+ also compresses the KV cache at runtime via -ctk and -ctv flags. This doesn't change the model file, just how much memory the context window uses. KV compression further reduces runtime memory usage, allowing larger context windows within the same hardware limits.

K cache (`-ctk`)	V cache (`-ctv`)	KV buffer (16K ctx)	Recommendation
f16	f16	2,480 MiB	default, short context
q8_0	turbo4	988 MiB (60% smaller)	recommended for long context
q8_0	turbo3	901 MiB (64% smaller)	aggressive, more KV savings

Download

bash

# Install huggingface-cli
brew install huggingface-cli
# or: pip install huggingface-hub

# Download
hf download pidtom/Gemma-4-31B-it-TQPlus Gemma-4-31B-it-Config-I.gguf --local-dir .

How to Run

bash

# Clone and build the TurboQuant+ fork
git clone https://github.com/TheTom/llama-cpp-turboquant.git
cd llama-cpp-turboquant
git checkout tqp-v0.1.0

# Build for Metal (macOS)
cmake -B build -DGGML_METAL=ON -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

# Build for CUDA (NVIDIA)
cmake -B build -DGGML_CUDA=ON -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

# Build for Vulkan
cmake -B build -DGGML_VULKAN=ON -DCMAKE_BUILD_TYPE=Release
cmake --build build -j

# Run (default KV cache)
./build/bin/llama-cli -m Gemma-4-31B-it-Config-I.gguf -ngl 99 -c 8192

# Run with recommended KV compression (for long context)
./build/bin/llama-cli -m Gemma-4-31B-it-Config-I.gguf -ngl 99 -c 32768 -ctk q8_0 -ctv turbo4

What is TurboQuant+?

TurboQuant+ applies Walsh-Hadamard Transform (WHT) domain quantization to compress model weights beyond standard GGUF quant types. This achieves lower bits-per-weight at equivalent or better quality by exploiting structured redundancy in the weight matrices.

Quantized by @pidtom | GitHub | X | Sponsor

thetom-ai/Gemma-4-31B-it-TQPlus

Gemma 4 31B-it — TurboQuant+ GGUF