NVFP4 GGUF quantization of Qwen3.5-4B, Alibaba Cloud's compact 4B multimodal foundation model with 262K context, 201 languages, and efficient hybrid Gated DeltaNet + Gated Attention architecture.

Optimized for NVIDIA Blackwell GPUs with native FP4 tensor core acceleration.

About NVFP4

What is NVFP4?

NVFP4 is NVIDIA's native 4-bit floating-point quantization format introduced with the Blackwell architecture (SM120+). Unlike traditional integer quantization (Q4_0, Q4_K_M, etc.), NVFP4 stores weights in FP4 (E4M3) format -- a 4-bit floating-point representation with 1 sign bit, 4 exponent bits, and 3 mantissa bits.

The key difference from INT4 formats:

Property	NVFP4 (FP4)	INT4 (Q4_X)
Representation	Floating-point	Integer
Dynamic range	~+-240	~+-7
Block size	16	32
Scale format	FP16 (E4M3)	FP16
Hardware support	Blackwell SM120+ (native tensor cores)	All GPUs (software)
Zero-shot perplexity	Near-identical to FP16	Slight degradation

Why use NVFP4?

Blackwell-native acceleration: NVFP4 is processed natively on Blackwell FP4 tensor cores, delivering up to 2x throughput vs INT4 software kernels on the same hardware.
Better dynamic range: Floating-point 4-bit preserves more information for outlier weights compared to integer quantization, resulting in lower perplexity degradation.
Memory efficiency: At ~4.74 bits per weight (BPW), a 4B model fits in ~2.5 GB -- well within 8 GB VRAM with room for 262K context.
No dequantization overhead: Unlike INT4 formats that require runtime dequantization, FP4 operates directly on tensor cores for both compute and memory bandwidth.

When to use NVFP4 vs other formats

NVFP4: Best choice if you have a Blackwell GPU (RTX 5060 Ti, RTX 5090, B200, etc.)
Q4_K_M / Q4_0: Better for pre-Blackwell GPUs (Ampere, Ada Lovelace) or CPU inference
Q8_0 / F16: Use when maximum quality is needed and memory is not a constraint

Files

Filename	Type	Size	Description
`qwen3.5-4b-nvfp4.gguf`	NVFP4	2.54 GB	Quantized text model weights
`mmproj-qwen3.5-4b-nvfp4-f16.gguf`	F16 mmproj	672 MB	Vision encoder projector

Quantization Details

Property	Value
Format	NVIDIA NVFP4 (E4M3 FP4)
Block size	16
Effective BPW	4.74
Hardware target	Blackwell SM120+
VRAM required (text)	~2.5 GB
VRAM required (text + vision + 32K ctx)	~4 GB

Model Description

Qwen3.5-4B features:

Hybrid architecture: Gated Delta Networks combined with Gated Attention in an efficient 8x(3xDeltaNet->FFN->1xAttention->FFN) pattern
262K context window: Native support for 262,144 token sequences
Vision capabilities: Built-in vision encoder for image understanding
Multi-Token Prediction: Trained with MTP for speculative decoding
Multilingual: Strong performance across 201 languages
Dense architecture: 32 layers, 2560 hidden dim, 16 GQA heads

Usage

llama.cpp (CLI)

bash

# Text + Image
llama-cli   -m qwen3.5-4b-nvfp4.gguf   --mmproj mmproj-qwen3.5-4b-nvfp4-f16.gguf   --image photo.jpg   -p "Describe this image in detail"

# Text only
llama-cli   -m qwen3.5-4b-nvfp4.gguf   -p "Explain quantum computing in simple terms"   -n 512

# OpenAI-compatible server
llama-server   -m qwen3.5-4b-nvfp4.gguf   --mmproj mmproj-qwen3.5-4b-nvfp4-f16.gguf   --port 8080

llama-cpp-python

python

from llama_cpp import Llama

llm = Llama.from_pretrained(
    repo_id="FreedomAISVR/Qwen3.5-4B-NVFP4-GGUF",
    filename="qwen3.5-4b-nvfp4.gguf",
    n_gpu_layers=-1,
)

response = llm.create_chat_completion([
    {"role": "user", "content": "What is the capital of France?"}
])
print(response["choices"][0]["message"]["content"])

Direct download

python

from huggingface_hub import hf_hub_download

for filename in ["qwen3.5-4b-nvfp4.gguf", "mmproj-qwen3.5-4b-nvfp4-f16.gguf"]:
    hf_hub_download(
        repo_id="FreedomAISVR/Qwen3.5-4B-NVFP4-GGUF",
        filename=filename,
        local_dir="./models"
    )

Quantization Pipeline

1. Download source weights
   huggingface_hub.snapshot_download("Qwen/Qwen3.5-4B")

2. Convert text model to F16 GGUF
   convert_hf_to_gguf.py --outtype f16

3. Extract vision encoder
   convert_hf_to_gguf.py --mmproj --outtype f16

4. Quantize to NVFP4
   llama-quantize qwen3.5-4b-f16.gguf qwen3.5-4b-nvfp4.gguf NVFP4

Hardware

Component	Specification
GPU	NVIDIA GeForce RTX 5060 Ti (Blackwell SM120)
VRAM	16 GB GDDR7
System RAM	64 GB DDR4

License

The original Qwen3.5-4B is released under Apache 2.0. These quantized weights inherit that license.