Model comparison
DeepSeek V4 Flash 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: DeepSeek V4 Flash #61 (Estimated); GPT-OSS 20B #159 (Supported). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. DeepSeek V4 Flash and GPT-OSS 20B share 1 comparable benchmark result. 0 of 8 categories are comparable. 21 results are unique to DeepSeek V4 Flash; 17 to GPT-OSS 20B.
Updated July 23, 2026- Shared results
- 1
- DeepSeek V4 Flash only
- 21
- GPT-OSS 20B only
- 17
- Comparable categories
- 0 / 8
Benchmark data for DeepSeek V4 Flash 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.
DeepSeek V4 Flash is priced at $0.14 input / $0.28 output per 1M tokens, versus $0.00 input / $0.00 output per 1M tokens for GPT-OSS 20B. DeepSeek V4 Flash has the larger context window at 1M, 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 | DeepSeek V4 Flash | Δ | GPT-OSS 20B |
|---|---|---|---|
| Agentic | DeepSeek V4 Flash49.1 | MarginNo overlap | GPT-OSS 20BNot measured |
| Coding | DeepSeek V4 Flash64.2 | MarginNo overlap | GPT-OSS 20BNot measured |
| Knowledge | DeepSeek V4 Flash38.8 | MarginNo overlap | GPT-OSS 20BNot measured |
| Math | DeepSeek V4 Flash40.8 | MarginNo overlap | GPT-OSS 20BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | DeepSeek V4 Flash | GPT-OSS 20B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | DeepSeek V4 Flash$0.14 input / $0.28 output | GPT-OSS 20B$0 input / $0 output | GPT-OSS 20B has the lower combined listed price. |
| Generation speedtokens per second | DeepSeek V4 FlashNot available | GPT-OSS 20B313 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | DeepSeek V4 FlashNot available | GPT-OSS 20B0.65 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | DeepSeek V4 Flash1M | GPT-OSS 20B128K | DeepSeek V4 Flash lists the larger context window. |
Benchmark Deep Dive
Agentic10 benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-OSS 20B | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 49.1% | — | Not comparable |
| MCP AtlasSource | 64% | — | Not comparable |
| ToolathlonSource | 40.7% | — | Not comparable |
| Claw-EvalSource | 57.8% | — | Not comparable |
| Gert LabsSource | 54.35% | — | Not comparable |
| AA Agentic IndexSource | — | 3.1% | Not comparable |
| APEX-Agents-AASource | — | 0.7% | Not comparable |
| τ²-bench resultsSource | — | 60.2% | Not comparable |
| GDPval-AASource | — | 3.0% | Not comparable |
| GDPval-AASource | — | 559 | Not comparable |
Coding7 benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-OSS 20B | Result |
|---|---|---|---|
| SWE-bench VerifiedSource | 73.7% | — | Not comparable |
| SWE-bench ProSource | 49.1% | — | Not comparable |
| SWE MultilingualSource | 69.7% | — | Not comparable |
| Terminal-Bench 2.0Source | 49.1% | — | Not comparable |
| React Native EvalsSource | — | 71% | Not comparable |
| AA Coding IndexSource | — | 20.7% | Not comparable |
| AA-SciCodeSource | — | 34.4% | Not comparable |
Reasoning4 benchmarks
Knowledge12 benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-OSS 20B | Result |
|---|---|---|---|
| MMLU-ProSource | 83% | — | Not comparable |
| SimpleQASource | 23.1% | — | Not comparable |
| Chinese-SimpleQASource | 71.5% | — | Not comparable |
| GPQASource | 71.2% | — | Not comparable |
| GPQA-DSource | 71.2% | — | Not comparable |
| HLESource | 8.1% | — | 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
Multimodal1 benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-OSS 20B | Result |
|---|---|---|---|
| Design Arena WebsiteSource | 1238 | 882 | DeepSeek V4 Flash leads |
Inst. Following1 benchmarks
| Benchmark | DeepSeek V4 Flash | GPT-OSS 20B | Result |
|---|---|---|---|
| AA-IFBenchSource | — | 65.1% | Not comparable |
Frequently Asked Questions (3)
Can I compare DeepSeek V4 Flash 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 DeepSeek V4 Flash and GPT-OSS 20B today?
DeepSeek V4 Flash: $0.14 input / $0.28 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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