Model comparison
DeepSeek V4 Flash (Max) vs GPT-5.1
Head-to-head evidence from 16 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: DeepSeek V4 Flash (Max) unranked (Not scored); GPT-5.1 #94 (Estimated). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. DeepSeek V4 Flash (Max) and GPT-5.1 share 16 comparable benchmark results. 1 of 8 categories are comparable. 29 results are unique to DeepSeek V4 Flash (Max); 5 to GPT-5.1.
Updated July 23, 2026- Shared results
- 16
- DeepSeek V4 Flash (Max) only
- 29
- GPT-5.1 only
- 5
- Comparable categories
- 1 / 8
Treat this as a split decision. DeepSeek V4 Flash (Max) makes more sense if mathematics is the priority or you want the cheaper token bill; GPT-5.1 is the better fit if its strengths line up with your actual workload.
Confidence note. This is a partial-evidence comparison with 16 shared benchmark results across 6 evidence categories; 1 of 8 categories currently have scoreable aggregates for both models. Treat the verdict as directional until coverage is more balanced.
Why this result
DeepSeek V4 Flash (Max) and GPT-5.1 finish on the same BenchAlign overall score, so this is less about a single winner and more about where the edge shows up. The BenchAlign headline says tie; the benchmark table is where the real choice happens.
GPT-5.1 is also the more expensive model on tokens at $1.25 input / $10.00 output per 1M tokens, versus $0.14 input / $0.28 output per 1M tokens for DeepSeek V4 Flash (Max). That is roughly 35.7x on output cost alone. DeepSeek V4 Flash (Max) gives you the larger context window at 1M, compared with 200K for GPT-5.1.
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 (Max) | Δ | GPT-5.1 |
|---|---|---|---|
| Math | DeepSeek V4 Flash (Max)94.8 | Margin← 68.4 | GPT-5.126.4 |
| Agentic | DeepSeek V4 Flash (Max)63.8 | MarginNo overlap | GPT-5.1Not measured |
| Coding | DeepSeek V4 Flash (Max)68.8 | MarginNo overlap | GPT-5.1Not measured |
| Knowledge | DeepSeek V4 Flash (Max)55.3 | MarginNo overlap | GPT-5.1Not measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | DeepSeek V4 Flash (Max) | GPT-5.1 | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | DeepSeek V4 Flash (Max)$0.14 input / $0.28 output | GPT-5.1$1.25 input / $10 output | DeepSeek V4 Flash (Max) has the lower combined listed price. |
| Generation speedtokens per second | DeepSeek V4 Flash (Max)Not available | GPT-5.1111 tok/s | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | DeepSeek V4 Flash (Max)Not available | GPT-5.157.47 s | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | DeepSeek V4 Flash (Max)1M | GPT-5.1200K | DeepSeek V4 Flash (Max) lists the larger context window. |
Benchmark Deep Dive
Agentic16 benchmarks
| Benchmark | DeepSeek V4 Flash (Max) | GPT-5.1 | Result |
|---|---|---|---|
| Terminal-Bench 2.0Source | 56.9% | — | Not comparable |
| BrowseCompSource | 73.2% | — | Not comparable |
| HLE w/ toolsSource | 45.1% | — | Not comparable |
| MCP AtlasSource | 69% | — | Not comparable |
| GDPval-AASource | 1189 | 987 | DeepSeek V4 Flash (Max) leads |
| ToolathlonSource | 47.8% | — | Not comparable |
| AA Agentic IndexSource | 31.1% | 21.0% | DeepSeek V4 Flash (Max) leads |
| τ²-bench resultsSource | 95% | 81.9% | DeepSeek V4 Flash (Max) leads |
| GDPval-AASource | 34.4% | 24.4% | DeepSeek V4 Flash (Max) leads |
| AA BriefcaseSource | 831 | — | Not comparable |
| AA EnterpriseOps-GymSource | 39.6% | — | Not comparable |
| AA Harvey LABSource | 81.3% | — | Not comparable |
| AA ITBenchSource | 31.5% | — | Not comparable |
| AA Tau3 BankingSource | 22.9% | — | Not comparable |
| terminalBenchHardSource | 35.6% | — | Not comparable |
| Gert LabsSource | — | 41.24% | Not comparable |
Coding8 benchmarks
| Benchmark | DeepSeek V4 Flash (Max) | GPT-5.1 | Result |
|---|---|---|---|
| CodeforcesSource | 3052.0 | — | Not comparable |
| SWE-bench VerifiedSource | 79% | — | Not comparable |
| SWE-bench ProSource | 52.6% | — | Not comparable |
| SWE MultilingualSource | 73.3% | — | Not comparable |
| Terminal-Bench 2.0Source | 56.9% | — | Not comparable |
| AA Coding IndexSource | 56.2% | 49.4% | DeepSeek V4 Flash (Max) leads |
| AA-SciCodeSource | 44.9% | 43.3% | DeepSeek V4 Flash (Max) leads |
| Vibe Code BenchSource | — | 24.61% | Not comparable |
Reasoning4 benchmarks
Knowledge13 benchmarks
| Benchmark | DeepSeek V4 Flash (Max) | GPT-5.1 | Result |
|---|---|---|---|
| MMLU-ProSource | 86.2% | — | Not comparable |
| SimpleQASource | 34.1% | — | Not comparable |
| Chinese-SimpleQASource | 78.9% | — | Not comparable |
| GPQASource | 88.1% | — | Not comparable |
| GPQA-DSource | 88.1% | — | Not comparable |
| HLESource | 34.8% | — | Not comparable |
| Artificial Analysis Intelligence IndexSource | 40.3% | 36.9% | DeepSeek V4 Flash (Max) leads |
| AA-GPQA DiamondSource | 89.4% | 87.3% | DeepSeek V4 Flash (Max) leads |
| AA-HLESource | 32.1% | 26.5% | DeepSeek V4 Flash (Max) leads |
| AA-Omniscience IndexSource | -22.9% | 5.6% | GPT-5.1 leads |
| AA-Omniscience AccuracySource | 37.2% | 37.6% | GPT-5.1 leads |
| AA-Omniscience Hallucination RateSource | 95.8% | 51.3% | GPT-5.1 leads |
| AA Openness IndexSource | 50.0% | — | Not comparable |
MathDeepSeek V4 Flash (Max) wins6 benchmarks
| Benchmark | DeepSeek V4 Flash (Max) | GPT-5.1 | Result |
|---|---|---|---|
| HMMT Feb 2026Source | 94.8% | — | Not comparable |
| IMOAnswerBenchSource | 88.4% | — | Not comparable |
| ApexSource | 33.0% | — | Not comparable |
| Apex ShortlistSource | 85.7% | — | Not comparable |
| FrontierMath v2 (Tiers 1-3)Source | — | 31.034% | Not comparable |
| FrontierMath v2 (Tier 4)Source | — | 12.500% | Not comparable |
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | DeepSeek V4 Flash (Max) | GPT-5.1 | Result |
|---|---|---|---|
| AA-IFBenchSource | 79.2% | 72.9% | DeepSeek V4 Flash (Max) leads |
Frequently Asked Questions (2)
Which is better, DeepSeek V4 Flash (Max) or GPT-5.1?
DeepSeek V4 Flash (Max) and GPT-5.1 are tied on the BenchAlign overall score, so the right pick depends on which category matters most for your use case.
Which is better for math, DeepSeek V4 Flash (Max) or GPT-5.1?
DeepSeek V4 Flash (Max) has the edge for math in this comparison, averaging 94.8 versus 26.4. GPT-5.1 stays close enough that the answer can still flip depending on your workload.
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