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

Model datasheet · Gemma 3

Gemma 3 12B

The conversationalist with eyes. Natural prose, good multilingual chat, and built-in image understanding. Weaker than same-size rivals at code and tool calling — pick it for writing and vision, not agents.

Vendor
Google
Architecture
Dense · 12.2B
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

6GB weights · e.g. Q3_K_M + KV: 832MB at 8K · 2.3GB at 32K · 8.3GB at 128K
Math & reasoning 3/10
data checked Aug 2026
  • quant-degradation-community — degradation reports @ Q3_K_M · aggregated · 2026-08-30

    Editorial derivation: standard ≤3-bit math cliff.

Creative writing 6/10
data checked Aug 2026
  • quant-degradation-community — community consensus @ Q3_K_M · aggregated · 2026-08-30

    Editorial derivation: prose survives low quants better than reasoning does.

Q4–Q5 — 4–5 bit

7GB weights · e.g. Q4_0 , Q4_K_M , mlx-4bit + KV: 832MB at 8K · 2.3GB at 32K · 8.3GB at 128K
Creative writing 7/10
data checked Aug 2026
  • quant-degradation-community — community consensus @ Q4_0 · aggregated · 2026-08-30

    Editorial derivation: Google ships QAT Q4_0 weights trained to preserve quality; prose holds up well at 4-bit.

Instruction following 7/10
data checked Aug 2026
  • community-consensus — community reputation (no IFEval-style benchmark published for this model) @ Q4_0 · aggregated · 2026-08-30

    Editorial score: chat-instruction reliability is a consistent community finding; QAT weights limit quant loss. No numeric benchmark backs this cell.

Coding 5/10
data checked Aug 2026
  • quant-degradation-community — community consensus @ Q4_0 · aggregated · 2026-08-30

    Editorial derivation from the vendor-reported full-band score; QAT limits quant loss.

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

    Editorial derivation: small loss vs the vendor-reported full band.

Q6–Q8 — 6–8 bit

10GB weights · e.g. Q6_K , Q8_0 + KV: 832MB at 8K · 2.3GB at 32K · 8.3GB at 128K

— Not yet rated · contributions welcome —

FP16 — full precision (fp16/bf16)

24GB weights · e.g. bf16 + KV: 832MB at 8K · 2.3GB at 32K · 8.3GB at 128K
Math & reasoning 5/10
data checked Aug 2026
Coding 5/10
data checked Aug 2026
  • vendor-model-cardHumanEval (0-shot) = 45.7 @ bf16 · vendor-reported · 2026-08-30

    MBPP (3-shot): 60.4. Absent from the Aider polyglot leaderboard (the 27B scores 4.9% there).

Factuality 6/10
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: Gemma 3's prose quality is a consistent community finding, but the model is absent from the current EQ-Bench Creative Writing v3 list (checked 2026-08-30). Treat as unverified-by-benchmark.

§2 Known issues & what fixes them

ISSUE-01 moderate Q2–Q3 / Q4–Q5 / Q6–Q8 / FP16 · tool-calling

Tool calling is unreliable at every precision — Gemma 3 was not trained with a strong native function-calling format, so agents built on it misfire.

Fix
Prompt technique [partial]

Strict system prompts with exact JSON examples improve reliability somewhat.

No fix
No known fix — choose a different model

For serious agent/MCP work, pick a Qwen3 model instead — this is a training gap, not a quant artifact.

Evidence · 2 sources · community-consensus
ISSUE-02 severe Q2–Q3 · math

Already mid-pack at math, and the ≤3-bit cliff makes multi-step arithmetic untrustworthy.

Fix
Move up a quant band [strong]

Google's QAT Q4_0 build is only ~1GB larger and much stronger — there is little reason to run this model below 4-bit.

Fix
Code interpreter / calculator tool [partial]

Offload arithmetic to a tool — but note this model's tool calling is itself weak, so verify your setup works.

Evidence · 2 sources · community-consensus