Model comparison
GPT-5.1 vs Mistral Medium 3.5 128B
Head-to-head evidence from 17 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: GPT-5.1 #94 (Estimated); Mistral Medium 3.5 128B unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. GPT-5.1 and Mistral Medium 3.5 128B share 17 comparable benchmark results. 0 of 8 categories are comparable. 4 results are unique to GPT-5.1; 8 to Mistral Medium 3.5 128B.
Updated July 23, 2026- Shared results
- 17
- GPT-5.1 only
- 4
- Mistral Medium 3.5 128B only
- 8
- Comparable categories
- 0 / 8
Benchmark data for GPT-5.1 and Mistral Medium 3.5 128B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 17 shared benchmark results across 6 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.
GPT-5.1 is priced at $1.25 input / $10.00 output per 1M tokens, versus $1.50 input / $7.50 output per 1M tokens for Mistral Medium 3.5 128B. Mistral Medium 3.5 128B has the larger context window at 256K, 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 | GPT-5.1 | Δ | Mistral Medium 3.5 128B |
|---|---|---|---|
| Coding | GPT-5.1Not measured | MarginNo overlap | Mistral Medium 3.5 128B77.6 |
| Math | GPT-5.126.4 | MarginNo overlap | Mistral Medium 3.5 128BNot measured |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | GPT-5.1 | Mistral Medium 3.5 128B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | GPT-5.1$1.25 input / $10 output | Mistral Medium 3.5 128B$1.5 input / $7.5 output | Mistral Medium 3.5 128B has the lower combined listed price. |
| Generation speedtokens per second | GPT-5.1111 tok/s | Mistral Medium 3.5 128BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | GPT-5.157.47 s | Mistral Medium 3.5 128BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | GPT-5.1200K | Mistral Medium 3.5 128B256K | Mistral Medium 3.5 128B lists the larger context window. |
Benchmark Deep Dive
Agentic11 benchmarks
| Benchmark | GPT-5.1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA Agentic IndexSource | 21.0% | 19.0% | GPT-5.1 leads |
| τ²-bench resultsSource | 81.9% | 94.2% | Mistral Medium 3.5 128B leads |
| Gert LabsSource | 41.24% | 39.10% | GPT-5.1 leads |
| GDPval-AASource | 24.4% | 21.4% | GPT-5.1 leads |
| GDPval-AASource | 987 | 929 | GPT-5.1 leads |
| τ³-bench resultsSource | — | 91.4% | Not comparable |
| AA BriefcaseSource | — | 506 | Not comparable |
| AA EnterpriseOps-GymSource | — | 33.7% | Not comparable |
| AA Harvey LABSource | — | 69.1% | Not comparable |
| AA Tau3 BankingSource | — | 14.4% | Not comparable |
| terminalBenchHardSource | — | 33.3% | Not comparable |
Coding4 benchmarks
Reasoning2 benchmarks
Knowledge7 benchmarks
| Benchmark | GPT-5.1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 36.9% | 29.9% | GPT-5.1 leads |
| AA-GPQA DiamondSource | 87.3% | 74.8% | GPT-5.1 leads |
| AA-HLESource | 26.5% | 12.8% | GPT-5.1 leads |
| AA-Omniscience IndexSource | 5.6% | -36.3% | GPT-5.1 leads |
| AA-Omniscience AccuracySource | 37.6% | 25.1% | GPT-5.1 leads |
| AA-Omniscience Hallucination RateSource | 51.3% | 82.0% | GPT-5.1 leads |
| AA Openness IndexSource | — | 33.3% | Not comparable |
Math2 benchmarks
Multimodal2 benchmarks
Inst. Following1 benchmarks
| Benchmark | GPT-5.1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA-IFBenchSource | 72.9% | 68.8% | GPT-5.1 leads |
Frequently Asked Questions (3)
Can I compare GPT-5.1 and Mistral Medium 3.5 128B 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-5.1 and Mistral Medium 3.5 128B today?
GPT-5.1: $1.25 input / $10.00 output per 1M tokens Mistral Medium 3.5 128B: $1.50 input / $7.50 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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