Model comparison
Gemma 4 12B vs GPT-OSS 20B
Head-to-head evidence from 11 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Gemma 4 12B #137 (Estimated); GPT-OSS 20B #159 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Gemma 4 12B and GPT-OSS 20B share 11 comparable benchmark results. 0 of 8 categories are comparable. 12 results are unique to Gemma 4 12B; 7 to GPT-OSS 20B.
Updated July 23, 2026- Shared results
- 11
- Gemma 4 12B only
- 12
- GPT-OSS 20B only
- 7
- Comparable categories
- 0 / 8
Benchmark data for Gemma 4 12B and GPT-OSS 20B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 11 shared benchmark results across 5 evidence categories; 0 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
BenchLM has partial data for these models, but not enough overlapping benchmark coverage to produce a fair score-level comparison yet.
Gemma 4 12B has the larger context window at 256K, compared with 128K for GPT-OSS 20B.
Category breakdown
Exact category averages are shown below. Not measured means BenchLM does not have enough sourced public coverage for that model and category.
| Category | Gemma 4 12B | Δ | GPT-OSS 20B |
|---|---|---|---|
| Reasoning | Gemma 4 12B43.4 | MarginNo overlap | GPT-OSS 20BNot measured |
| Knowledge | Gemma 4 12B77.5 | MarginNo overlap | GPT-OSS 20BNot measured |
| Math | Gemma 4 12B77.5 | MarginNo overlap | GPT-OSS 20BNot measured |
| Multimodal | Gemma 4 12B69.1 | MarginNo overlap | GPT-OSS 20BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Gemma 4 12B | GPT-OSS 20B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Gemma 4 12BNot available | GPT-OSS 20B$0 input / $0 output | A complete price comparison is not available. |
| Generation speedtokens per second | Gemma 4 12BNot available | GPT-OSS 20B313 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Gemma 4 12BNot available | GPT-OSS 20B0.65 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Gemma 4 12B256K | GPT-OSS 20B128K | Gemma 4 12B lists the larger context window. |
Benchmark Deep Dive
Agentic5 benchmarks
Coding3 benchmarks
Reasoning4 benchmarks
Knowledge11 benchmarks
| Benchmark | Gemma 4 12B | GPT-OSS 20B | Result |
|---|---|---|---|
| GPQASource | 78.8% | — | Not comparable |
| GPQA-DSource | 78.8% | — | Not comparable |
| MMLU-ProSource | 77.2% | — | Not comparable |
| HLE w/o toolsSource | 5.2% | — | Not comparable |
| MMMLUSource | 83.4% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 22.0% | 14.9% | Gemma 4 12B leads |
| AA-GPQA DiamondSource | 75.3% | 68.8% | Gemma 4 12B leads |
| AA-HLESource | 14.8% | 9.8% | Gemma 4 12B leads |
| AA-Omniscience IndexSource | -51.9% | -63.9% | Gemma 4 12B leads |
| AA-Omniscience AccuracySource | 16.0% | 15.5% | Gemma 4 12B leads |
| AA-Omniscience Hallucination RateSource | 80.8% | 94.1% | Gemma 4 12B leads |
Math1 benchmarks
| Benchmark | Gemma 4 12B | GPT-OSS 20B | Result |
|---|---|---|---|
| AIME26Source | 77.5% | — | Not comparable |
Multimodal5 benchmarks
Inst. Following1 benchmarks
| Benchmark | Gemma 4 12B | GPT-OSS 20B | Result |
|---|---|---|---|
| AA-IFBenchSource | 73.5% | 65.1% | Gemma 4 12B leads |
Frequently Asked Questions (3)
Can I compare Gemma 4 12B and GPT-OSS 20B on BenchLM yet?
Not fully yet. BenchLM is tracking both models, but the sourced benchmark breakdown for this comparison is still coming soon.
Why does this comparison show “coming soon”?
BenchLM only shows category winners and benchmark-level calls when we have sourced results that can be compared fairly. For these models, the public benchmark coverage is not complete enough yet.
What data is available for Gemma 4 12B and GPT-OSS 20B today?
GPT-OSS 20B: $0.00 input / $0.00 output per 1M tokens Both model pages still include creator, context window, reasoning mode, and other metadata while benchmark coverage fills in.
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