Known-issues sheets for local language models Rev 0.1.0 · reviewed every 7 days

Model datasheet · Gemma 3

Gemma 3 27B

The conversationalist at scale: best-in-family prose, strong multilingual chat, real vision — and the receipts show it is NOT a coding or agent model (Aider 4.9%).

Vendor
Google
Architecture
Dense · 27B
Context
131,072 tokens
License
Gemma Terms of Use
Released
2025-03-12
Vision
Yes

→ GGUF (llama.cpp / LM Studio / Ollama) → MLX (Apple Silicon)

§1 Characteristics by quantization band

Q2–Q3 — 2–3 bit

13GB weights · e.g. Q3_K_M + KV: 1GB at 8K · 2.9GB at 32K · 10.4GB at 128K

— Not yet rated · contributions welcome —

Q4–Q5 — 4–5 bit

17GB weights · e.g. Q4_0 , Q4_K_M , mlx-4bit + KV: 1GB at 8K · 2.9GB at 32K · 10.4GB at 128K
Creative writing 7/10
data checked Aug 2026
  • quant-degradation-community — community consensus @ Q4_0 · aggregated · 2026-08-30

    Editorial derivation: Google's QAT Q4_0 preserves prose quality well.

Math & reasoning 4/10
data checked Aug 2026
  • quant-degradation-community — community consensus @ Q4_0 · aggregated · 2026-08-30

    Editorial derivation: small loss vs full band; QAT helps.

Coding 4/10
data checked Aug 2026

Q6–Q8 — 6–8 bit

22GB weights · e.g. Q6_K + KV: 1GB at 8K · 2.9GB at 32K · 10.4GB at 128K

— Not yet rated · contributions welcome —

FP16 — full precision (fp16/bf16)

54GB weights · e.g. bf16 + KV: 1GB at 8K · 2.9GB at 32K · 10.4GB at 128K
Math & reasoning 5/10
data checked Aug 2026
Coding 4/10
data checked Aug 2026
Factuality 5/10
data checked Aug 2026
Creative writing 7/10
data checked Aug 2026
  • community-consensus — community reputation (no public benchmark currently lists this model) @ bf16 · aggregated · 2026-08-30

    Editorial score: the Gemma 3 prose reputation, strongest at 27B. No benchmark backs this cell.

§2 Known issues & what fixes them

ISSUE-01 severe Q2–Q3 / Q4–Q5 / Q6–Q8 / FP16 · coding

Real-world code editing is dismal — 4.9% on the Aider polyglot board, near the bottom, despite a respectable-looking HumanEval. Snippet benchmarks flatter it; repository work exposes it.

No fix
No known fix — choose a different model

Use a Qwen3 model for coding. Gemma's lane is chat, languages, writing, and vision.

Evidence · 2 sources · community-consensus
ISSUE-02 moderate Q2–Q3 / Q4–Q5 / Q6–Q8 / FP16 · tool-calling

No native function-calling tokens or template — tool use rides on prompt-following, which works surprisingly well but breaks more than trained-in tool calling.

Fix
Prompt technique [partial]

Give exact JSON schemas with examples in the system prompt — community benchmarks show it follows them decently.

No fix
No known fix — choose a different model

For heavy MCP/agent work, pick a model with trained-in tool calling.

Evidence · 2 sources · community-consensus
ISSUE-03 mild Q2–Q3 / Q4–Q5 / Q6–Q8 / FP16 · factuality

Family-wide tendency to hallucinate names and specific factual details; HHEM (7.4%) is oddly worse than the 4B.

Fix
RAG (retrieval) [strong]

Ground factual work; treat unsourced names/dates with suspicion.

Evidence · 1 source · anecdotal