Gemma 4 — Google's Open Model That Rewrites the Rules

Gemma 4: Google's Open Model That Rewrites the Rules

On April 2, 2026, Google released Gemma 4 — the first Gemma model under the Apache 2.0 license — and it immediately landed at #3 on the Chatbot Arena leaderboard, setting a new standard for open models.

A 31B parameter model competing with GPT-4o and Claude 3.5 Sonnet. A 3.8B active-parameter MoE model running on a single consumer GPU. Edge models that fit in under 1.5GB of RAM. Four model variants, 256K context, multimodal (text + image + audio). Let's break it all down.

The Gemma 4 Lineup

Key Points

• Apache 2.0: First for the Gemma series. Full commercial use, modification, and redistribution. A major shift from Gemma 3's restrictive license.
• MoE Architecture: The 26B model activates only 3.8B of its 26B parameters during inference. Memory and compute costs drop dramatically.
• 256K Context: All models support 256K tokens. Analyze entire codebases and long documents.
• Multimodal: Text, image, and audio input. Native aspect-ratio handling for images.

Benchmarks: How Much Better Than Gemma 3?

Gemma 4 31B vs Gemma 3 27B:

89.2% on AIME 2026 is staggering. Gemma 3 scored 20.8%. This isn't an incremental improvement — it's a generational leap in mathematical reasoning.

Codeforces ELO 2150 puts it at human Master level. Best-in-class among open models for competitive programming.

Architecture: What Changed

Dense Model (31B)

Standard Transformer architecture with several optimizations:

• Hybrid Attention: Sliding Window + Global Attention. Efficiently handles both local and long-range context.
• GQA (Grouped Query Attention): Groups Key-Value heads to reduce memory footprint.
• Per-layer Embeddings: Independent embeddings per layer for richer representations.
• QK/V Normalization: Normalizes queries, keys, and values for training stability.
• Proportional RoPE: Proportional positional encoding that maintains performance at long contexts.
• Softcapping: Bounds logit values to prevent extreme probability distributions.

MoE Model (26B/A4B)

Mixture-of-Experts with 26B total parameters, 3.8B active during inference:

• Expert layers placed independently between dense layers
• Router selects appropriate experts per input token
• Extreme parameter efficiency — Arena #6 with just 3.8B active parameters is unprecedented

Edge Models (E4B, E2B)

• E2B runs in under 1.5GB of memory
• Raspberry Pi 5: 133 tok/s prefill, 7.6 tok/s decode
• Designed for mobile, IoT, and embedded devices

Competitive Landscape

vs Qwen 3.5 (Alibaba)

Gemma 4 leads in benchmarks, edge lineup, and audio support.

vs Llama 4 (Meta)

Llama 4's 10M token context is impressive, but Gemma 4 wins on Arena ranking and licensing. Meta's Llama License requires separate licensing for 700M+ monthly users and prohibits using outputs to train competing models.

Ecosystem: Day-One Support

Major inference frameworks supported from launch:

• llama.cpp: GGUF quantized models available immediately
• Ollama: ollama run gemma4 — one command to run locally
• vLLM: Production serving optimized
• LM Studio: Local GUI-based execution
• transformers.js: Run in the browser
• Google AI Studio: Free API access

Running Locally with Ollama

# 31B Dense model
ollama run gemma4:31b

# 26B MoE model (lightweight)
ollama run gemma4:26b

# Edge model
ollama run gemma4:e2b

Fine-Tuning: LoRA Customization

Gemma 4 supports 140+ languages out of the box, but domain or style-specific tasks benefit from fine-tuning.

Thanks to Gemma 4's Apache 2.0 license, commercial distribution of fine-tuned models is fully unrestricted — the biggest licensing change from previous Gemma versions.

MoE models require a different LoRA approach than Dense — which Expert layers to target, why the Router stays frozen, how to adjust learning rates. We've put together a full series covering theory through production code.

Who Should Use What?

Gemma 4 31B (Dense):

• Production services demanding peak performance
• RAG pipelines, code generation, complex reasoning
• GPU server environments (A100/H100)

Gemma 4 26B/A4B (MoE):

• High performance on local GPUs
• Best model you can run on a single RTX 4090
• Maximum performance-per-dollar

Gemma 4 E4B/E2B (Edge):

• Mobile app integration
• IoT/embedded systems
• Offline-capable environments

Conclusion

Gemma 4 matters for three reasons:

1. Apache 2.0: A new licensing standard for open models. Use, modify, and distribute commercially with zero restrictions.
2. Performance: Arena #3 proves open models can compete head-to-head with closed ones.
3. Edge lineup: Models running in under 1.5GB on a Raspberry Pi — the practical start of on-device AI.

The MoE model (26B/A4B) is particularly impressive. Arena #6 with only 3.8B active parameters sets a new benchmark for parameter efficiency. For developers wanting to run powerful LLMs locally, this is the most compelling option available today.

References

• Gemma 4 Official Blog
• Google AI Studio
• Hugging Face Gemma 4
• Technical Report