Model comparison
Grok Code Fast 1 vs Mistral Medium 3.5 128B
Head-to-head evidence from 12 shared benchmark results across 5 categories. Overall scores shown here use the public BenchAlign v5 ranking lane.
Public leaderboard positions: Grok Code Fast 1 #189 (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 Code Fast 1 and Mistral Medium 3.5 128B share 12 comparable benchmark results. 1 of 8 categories are comparable. 0 results are unique to Grok Code Fast 1; 13 to Mistral Medium 3.5 128B.
Updated July 27, 2026- Shared results
- 12
- Grok Code Fast 1 only
- 0
- Mistral Medium 3.5 128B only
- 13
- Comparable categories
- 1 / 8
Treat this as a split decision. Grok Code Fast 1 makes more sense if you want the cheaper token bill or you would rather avoid the extra latency and token burn of a reasoning model; Mistral Medium 3.5 128B is the better fit if coding is the priority or you want the stronger reasoning-first profile.
Confidence note. This is a partial-evidence comparison with 12 shared benchmark results across 5 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
Grok Code Fast 1 and Mistral Medium 3.5 128B 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.
Mistral Medium 3.5 128B is also the more expensive model on tokens at $1.50 input / $7.50 output per 1M tokens, versus $0.20 input / $1.50 output per 1M tokens for Grok Code Fast 1. That is roughly 5.0x on output cost alone. Mistral Medium 3.5 128B is the reasoning model in the pair, while Grok Code Fast 1 is not. That usually helps on harder chain-of-thought-heavy tests, but it can also mean more latency and more token spend in real use.
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 Code Fast 1 | Δ | Mistral Medium 3.5 128B |
|---|---|---|---|
| Coding | Grok Code Fast 170.8 | Margin→ 6.8 | Mistral Medium 3.5 128B77.6 |
Decisive benchmark drivers
The largest measured benchmark gaps in this matchup, with exact reported values.
More
- Source ↗
SWE-bench Verified
CodingA 70.8%B 77.6%Winner: Mistral Medium 3.5 128BΔ 6.8SWE-bench Verified: Grok Code Fast 1 scored 70.8%; Mistral Medium 3.5 128B scored 77.6%. Mistral Medium 3.5 128B wins this benchmark.
Operational comparison
Runtime and commercial metrics are compared only when both models have a complete sourced value.
| Metric | Grok Code Fast 1 | Mistral Medium 3.5 128B | Comparison |
|---|---|---|---|
| Input / output priceUSD per 1M tokens | Grok Code Fast 1$0.2 input / $1.5 output | Mistral Medium 3.5 128B$1.5 input / $7.5 output | Grok Code Fast 1 has the lower combined listed price. |
| Generation speedtokens per second | Grok Code Fast 1172 tok/s | Mistral Medium 3.5 128BNot available | A complete speed comparison is not available. |
| First-answer latencyseconds to first token | Grok Code Fast 12.81 s | Mistral Medium 3.5 128BNot available | A complete latency comparison is not available. |
| Context windowmaximum listed tokens | Grok Code Fast 1256K | Mistral Medium 3.5 128B256K | Listed context windows are equal. |
Benchmark Deep Dive
Agentic11 benchmarks
| Benchmark | Grok Code Fast 1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| τ²-bench resultsSource | 75.7% | 94.2% | Mistral Medium 3.5 128B 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 |
| Gert LabsSource | — | 39.10% | 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 |
CodingMistral Medium 3.5 128B wins3 benchmarks
Reasoning2 benchmarks
Knowledge7 benchmarks
| Benchmark | Grok Code Fast 1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| Artificial Analysis Intelligence IndexSource | 21.6% | 29.9% | Mistral Medium 3.5 128B leads |
| AA-GPQA DiamondSource | 72.7% | 74.8% | Mistral Medium 3.5 128B leads |
| AA-HLESource | 7.5% | 12.8% | Mistral Medium 3.5 128B leads |
| AA-Omniscience IndexSource | -36.0% | -36.3% | Grok Code Fast 1 leads |
| AA-Omniscience AccuracySource | 23.8% | 25.1% | Mistral Medium 3.5 128B leads |
| AA-Omniscience Hallucination RateSource | 78.5% | 82.0% | Grok Code Fast 1 leads |
| AA Openness IndexSource | — | 33.3% | Not comparable |
Multimodal1 benchmarks
| Benchmark | Grok Code Fast 1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA-MMMU-ProSource | — | 64.9% | Not comparable |
Inst. Following1 benchmarks
| Benchmark | Grok Code Fast 1 | Mistral Medium 3.5 128B | Result |
|---|---|---|---|
| AA-IFBenchSource | 41.4% | 68.8% | Mistral Medium 3.5 128B leads |
Frequently Asked Questions (2)
Which is better, Grok Code Fast 1 or Mistral Medium 3.5 128B?
Grok Code Fast 1 and Mistral Medium 3.5 128B 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 coding, Grok Code Fast 1 or Mistral Medium 3.5 128B?
Mistral Medium 3.5 128B has the edge for coding in this comparison, averaging 77.6 versus 70.8. Inside this category, SWE-bench Verified is the benchmark that creates the most daylight between them.
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