Model comparison
Grok 4.1 Fast vs Mistral Medium 3.5 128B
Head-to-head evidence from 13 shared benchmark results across 6 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Grok 4.1 Fast #110 (Supported); Mistral Medium 3.5 128B unranked (Not scored). Intervals and evidence labels describe ranking uncertainty, not a guarantee for a specific workload.
Evidence parity. Grok 4.1 Fast and Mistral Medium 3.5 128B share 13 comparable benchmark results. 0 of 8 categories are comparable. 0 results are unique to Grok 4.1 Fast; 12 to Mistral Medium 3.5 128B.
Updated July 27, 2026- Shared results
- 13
- Grok 4.1 Fast only
- 0
- Mistral Medium 3.5 128B only
- 12
- Comparable categories
- 0 / 8
Benchmark data for Grok 4.1 Fast and Mistral Medium 3.5 128B is coming soon on BenchLM.
Confidence note. This is a partial-evidence comparison with 13 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.
Mistral Medium 3.5 128B is priced at $1.50 input / $7.50 output per 1M tokens, versus $0.20 input / $0.50 output per 1M tokens for Grok 4.1 Fast. Grok 4.1 Fast has the larger context window at 1M, compared with 256K for Mistral Medium 3.5 128B.
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 | Grok 4.1 Fast | Δ | Mistral Medium 3.5 128B |
|---|---|---|---|
| Coding | Grok 4.1 FastNot measured | MarginNo overlap | Mistral Medium 3.5 128B77.6 |
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Grok 4.1 Fast | Mistral Medium 3.5 128B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Grok 4.1 Fast$0.2 input / $0.5 output | Mistral Medium 3.5 128B$1.5 input / $7.5 output | Grok 4.1 Fast has the lower combined listed price. |
| Generation speedtokens per second | Grok 4.1 Fast138 tok/s | Mistral Medium 3.5 128BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Grok 4.1 Fast0.54 s | Mistral Medium 3.5 128BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Grok 4.1 Fast1M | Mistral Medium 3.5 128B256K | Grok 4.1 Fast lists the larger context window. |
Benchmark Deep Dive
Agentic11 benchmarks
| Benchmark | Grok 4.1 Fast | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| τ²-bench resultsSource | 63.7% | 94.2% | Mistral Medium 3.5 128B leads |
| Gert LabsSource | 47.32% | 39.10% | Grok 4.1 Fast leads |
| τ³-bench resultsSource | — | 91.4% | Not comparable |
| AA Agentic IndexSource | — | 19.0% | Not comparable |
| GDPval-AASource | — | 21.6% | Not comparable |
| GDPval-AASource | — | 933 | Not comparable |
| AA EnterpriseOps-GymSource | — | 33.7% | Not comparable |
| AA Harvey LABSource | — | 69.1% | Not comparable |
| terminalBenchHardSource | — | 33.3% | Not comparable |
| AA BriefcaseSource | — | 516 | Not comparable |
| AA Tau3 BankingSource | — | 14.4% | Not comparable |
Coding3 benchmarks
Reasoning2 benchmarks
Knowledge7 benchmarks
| Benchmark | Grok 4.1 Fast | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 16.9% | 29.9% | Mistral Medium 3.5 128B leads |
| AA-GPQA DiamondSource | 63.7% | 74.8% | Mistral Medium 3.5 128B leads |
| AA-HLESource | 5.0% | 12.8% | Mistral Medium 3.5 128B leads |
| AA-Omniscience IndexSource | -50.9% | -36.3% | Mistral Medium 3.5 128B leads |
| AA-Omniscience AccuracySource | 17.0% | 25.1% | Mistral Medium 3.5 128B leads |
| AA-Omniscience Hallucination RateSource | 81.8% | 82.0% | Grok 4.1 Fast leads |
| AA Openness IndexSource | — | 33.3% | Not comparable |
Multimodal1 benchmarks
| Benchmark | Grok 4.1 Fast | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA-MMMU-ProSource | 48.4% | 64.9% | Mistral Medium 3.5 128B leads |
Inst. Following1 benchmarks
| Benchmark | Grok 4.1 Fast | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA-IFBenchSource | 36.5% | 68.8% | Mistral Medium 3.5 128B leads |
Frequently Asked Questions (3)
Can I compare Grok 4.1 Fast 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 Grok 4.1 Fast and Mistral Medium 3.5 128B today?
Grok 4.1 Fast: $0.20 input / $0.50 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.
Related Comparisons
Explore More
Know when it’s worth switching models
The model to choose, the cheaper alternative, and the release we would wait on.
One email each week. Unsubscribe anytime.