Model comparison
GPT-5.4 Pro vs GPT-OSS 20B
Head-to-head evidence from 1 shared benchmark result across 1 category. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.4 Pro #44 (Estimated); GPT-OSS 20B #159 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.4 Pro and GPT-OSS 20B share 1 comparable benchmark result. 0 of 8 categories are comparable. 11 results are unique to GPT-5.4 Pro; 17 to GPT-OSS 20B.
Updated July 23, 2026- Shared results
- 1
- GPT-5.4 Pro only
- 11
- GPT-OSS 20B only
- 17
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.4 Pro and GPT-OSS 20B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 1 shared benchmark result across 1 evidence category; 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.
GPT-5.4 Pro is priced at $30.00 input / $180.00 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for GPT-OSS 20B. GPT-5.4 Pro has the larger context window at 1.05M, 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 | GPT-5.4 Pro | Δ | GPT-OSS 20B |
|---|---|---|---|
| Agentic | GPT-5.4 Pro89.3 | MarginNo overlap | GPT-OSS 20BNot measured |
| Reasoning | GPT-5.4 Pro83.3 | MarginNo overlap | GPT-OSS 20BNot measured |
| Knowledge | GPT-5.4 Pro58.7 | MarginNo overlap | GPT-OSS 20BNot measured |
| Math | GPT-5.4 Pro46.9 | MarginNo overlap | GPT-OSS 20BNot measured |
| Multimodal | GPT-5.4 Pro94.0 | MarginNo overlap | GPT-OSS 20BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.4 Pro | GPT-OSS 20B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.4 Pro$30 input / $180 output | GPT-OSS 20B$0 input / $0 output | GPT-OSS 20B has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.4 Pro74 tok/s | GPT-OSS 20B313 tok/s | GPT-OSS 20B has the higher measured throughput. |
| First-answer latencyseconds to first token | GPT-5.4 Pro151.79 s | GPT-OSS 20B0.65 s | GPT-OSS 20B reaches the first token sooner. |
| Context windowmaximum listed tokens | GPT-5.4 Pro1.05M | GPT-OSS 20B128K | GPT-5.4 Pro lists the larger context window. |
Benchmark Deep Dive
Agentic6 benchmarks
Coding3 benchmarks
Reasoning3 benchmarks
Knowledge10 benchmarks
| Benchmark | GPT-5.4 Pro | GPT-OSS 20B | Result |
|---|---|---|---|
| HLESource | 58.7% | — | Not comparable |
| FrontierScienceSource | 36.7% | — | Not comparable |
| FrontierScience ResearchSource | 36.7% | — | Not comparable |
| HLE w/o toolsSource | 42.7% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | — | 14.9% | Not comparable |
| AA-GPQA DiamondSource | — | 68.8% | Not comparable |
| AA-HLESource | — | 9.8% | Not comparable |
| AA-Omniscience IndexSource | — | -63.9% | Not comparable |
| AA-Omniscience AccuracySource | — | 15.5% | Not comparable |
| AA-Omniscience Hallucination RateSource | — | 94.1% | Not comparable |
Math4 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.4 Pro | GPT-OSS 20B | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 65.1% | Not comparable |
Frequently Asked Questions (3)
Can I compare GPT-5.4 Pro 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 GPT-5.4 Pro and GPT-OSS 20B today?
GPT-5.4 Pro: $30.00 input / $180.00 output per 1M tokens 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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