At a Glance
Table with columns: Property, Value| Property | Value |
|---|
| Base model | google/gemma-4-e4b-it |
| Architecture | Sparse MoE, 128 experts, hybrid sliding+global attention + SigLIP vision |
| Quant method | datafree RTN (QuantizationModifier; AutoRound blocked) |
| Quant scheme | W4A16 (4-bit weights, 16-bit activations) |
| Quant format | compressed-tensors (native vLLM) |
| Quantized | language_model.* — all Linear layers (attn + MLP) |
| Kept BF16 | vision_tower, audio_tower, multi_modal_projector, embed_tokens_per_layer (PLE), per_layer_model_projection (PLE), lm_head, norms, embeddings |
| Disk size | ~14 GB |
| Min GPU | 1× RTX 3090 24GB |
PLE layers kept at BF16
embed_tokens_per_layer and per_layer_model_projection implement Per-Layer Embeddings — ablations show catastrophic output degradation if quantized. Always excluded.
Memory Requirements
Table with columns: Configuration, BF16, This Quant (W4A16)| Configuration | BF16 | This Quant (W4A16) |
|---|
| Weights (disk/VRAM) | ~28 GB | ~14 GB |
| KV cache @ 32k ctx (fp8) | ~2.0 GB | ~2.0 GB |
| Total @ 32k ctx | ~30 GB | ~16 GB |
| Minimum GPU | A100 40GB | 1× RTX 3090 24GB |
The 4B active parameters (MoE) keep activation memory low. The full 26B+ parameter count still requires significant weight VRAM — W4A16 halves that requirement.
Quick Start
Tested with vLLM v0.21.0 (vllm/vllm-openai:v0.21.0-cu129-ubuntu2404). Weights are in compressed-tensors format — vLLM detects and loads quantization automatically. No --quantization flag needed.
vLLM
docker run --gpus device=0 -p 8080:8080 \
vllm/vllm-openai:v0.21.0-cu129-ubuntu2404 vllm serve \
88plug/Gemma4-E4B-it-W4A16 \
--kv-cache-dtype fp8 \
--max-model-len 32768 \
--gpu-memory-utilization 0.90
Weights are in compressed-tensors format — no --quantization flag needed.
Python client
from openai import OpenAI
client = OpenAI(base_url="http://localhost:8080/v1", api_key="x")
response = client.chat.completions.create(
model="88plug/Gemma4-E4B-it-W4A16",
messages=[{"role": "user", "content": "Explain sparse mixture-of-experts in two sentences."}],
max_tokens=256,
)
print(response.choices[0].message.content)
Quantization Design
The recipe targets all Linear modules in the LLM backbone with W4A16 (4-bit symmetric weight quantization, activations remain BF16). The following are excluded and kept at BF16:
Table with columns: Excluded pattern, Reason| Excluded pattern | Reason |
|---|
lm_head | Output projection — quality-sensitive |
.*embed_tokens$ | Token embeddings |
.*norm$ | Layer norms |
.*embed_tokens_per_layer.* | PLE: per-layer token embeddings — catastrophic if quantized |
.*per_layer_model_projection.* | PLE: projection into hidden dim — catastrophic if quantized |
|
All self_attn.{q,k,v,o}_proj and mlp.{gate,up,down}_proj layers across all transformer blocks are quantized to W4A16.
Calibration: 1024 samples — 512 from HuggingFaceH4/ultrachat_200k (chat) + 512 from wikitext-103-raw-v1 (text), max sequence length 2048.
Competitor Comparables
Table with columns: Model, Source, Format, Compare angle| Model | Source | Format | Compare angle |
|---|
google/gemma-4-e4b-it | official | BF16 | quality ceiling |
RedHatAI/gemma-3n-E4B-it-quantized.w4a16 | RedHatAI | compressed-tensors W4A16 | same format, prior generation |
88plug/Gemma4-E4B-it-W8A16 | 88plug | compressed-tensors W8A16 | higher precision variant |
First-to-market note: No compressed-tensors W4A16 quant found for gemma-4-e4b-it at release time. This is the first vLLM-native W4A16 for Gemma4 E4B.
Benchmarks
Results pending.
Table with columns: Engine, Format, Batch, ctx, tok/s, TTFT p50, TTFT p99, VRAM| Engine | Format | Batch | ctx | tok/s | TTFT p50 | TTFT p99 | VRAM |
|---|
| vLLM v0.21.0 | W4A16 compressed-tensors | 1 | 32k | — | — | — | — |
| vLLM v0.21.0 | W4A16 compressed-tensors | 8 | 32k | — |
Hardware: A6000 48 GB, CUDA 12.9, driver 570.
Quality Targets
Table with columns: Metric, Target| Metric | Target |
|---|
| KL divergence vs BF16 | < 0.014 |
| MMLU recovery | ≥ 99% |
SGLang Note
SGLang does not natively support compressed-tensors weights. To use SGLang, run the BF16 base model (google/gemma-4-e4b-it) directly:
docker run --gpus device=0 -p 30000:30000 \
lmsysorg/sglang:v0.5.8-cu129 python -m sglang.launch_server \
--model-path google/gemma-4-e4b-it \
--tp 1 \
--mem-fraction-static 0.85 \
--port 30000
SGLang benchmark results above reflect BF16 baseline throughput, not this quant.
llama.cpp / GGUF
Convert from the BF16 base checkpoint — not from compressed-tensors weights. VLM requires a separate mmproj GGUF for image input.
python convert_hf_to_gguf.py google/gemma-4-e4b-it \
--outfile Gemma4-E4B-BF16.gguf
python convert_hf_to_gguf.py google/gemma-4-e4b-it \
--mmproj --outfile Gemma4-E4B-mmproj.gguf
llama-quantize Gemma4-E4B-BF16.gguf Gemma4-E4B-Q8_0.gguf Q8_0
llama-quantize --imatrix calibration_datav3.txt \
Gemma4-E4B-BF16.gguf Gemma4-E4B-IQ4_XS.gguf IQ4_XS
llama-server \
--model Gemma4-E4B-Q8_0.gguf \
--mmproj Gemma4-E4B-mmproj.gguf \
--n-gpu-layers 999 \
--ctx-size 32768 \
--port 8081
Citation
@misc{gemma4report,
title = {Gemma 4 Technical Report},
author = {Google DeepMind},
year = {2025},
url = {https://huggingface.co/google/gemma-4-e4b-it}
}
About
88plug AI Lab produces production-grade compressed-tensors quantizations of frontier LLMs, VLMs, and omni models — built for native vLLM v0.21.0+ deployment with zero extra flags.
W8A16 — INT8 weights + BF16 activations. Near-lossless on any Ampere+ GPU. Runs where FP8 hardware cannot.
W4A16 — AutoRound with iters=200 and a mixed calibration corpus. Targets ≥ 99% MMLU recovery — the quality bar that makes W4A16 viable for production.
All weights are in compressed-tensors format. vLLM detects quantization automatically from quantization_config in config.json. No --quantization flag required.
Also available: Gemma4-E4B-it-W8A16 (INT8, ~5 GB) · Gemma4-E4B-it-W4A16 (INT4, ~14 GB)
Browse all releases → huggingface.co/88plug