Model comparison
Granite 3.1 8b Instruct vs Grok 4 Fast
Grok 4 Fast is the stronger model overall, scoring 39.0 to 31.8 on the Noometry Index.
Last verified . 12 shared benchmarks.
Summary
- They share 12 benchmarks with published results for both. Granite 3.1 8b Instruct scores higher in 1 category and Grok 4 Fast in 8 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 35.2.
- Granite 3.1 8b Instruct has downloadable open weights; the other is API-only.
Side by side
| Granite 3.1 8b Instruct | Grok 4 Fast | |
|---|---|---|
| Provider | IBM | xAI |
| Noometry Index | 31.8 | 39.0 |
| Released | — | 2025-09-19 |
| Weights | Open | Proprietary |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 13 | 30 |
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Category by category
Coding Granite 3.1 8b Instruct leads
Granite 3.1 8b Instruct: 33.9 (#232), Grok 4 Fast: 32.3 (#264)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Coding | 1186 | 1429 |
| LMArena WebDev | — | 1160 |
| WeirdML | — | 42.9% |
Agentic & Tool Use Grok 4 Fast leads
Granite 3.1 8b Instruct: 23.9 (#113), Grok 4 Fast: 29.3 (#80)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| Berkeley Function Calling Leaderboard | 27.1% | — |
| τ²-bench Banking | — | 15.7% |
| Cybench | — | 30% |
| LMArena Search | — | 1171 |
Reasoning Grok 4 Fast leads
Granite 3.1 8b Instruct: 21.2 (#204), Grok 4 Fast: 22.5 (#179)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Hard Prompts | 1146 | 1413 |
| ARC-AGI-2 | — | 5.3% |
| Kagi LLM Benchmark | — | 66.1% |
| ARC-AGI-1 | — | 48.5% |
| DTBench | — | 82.7% |
| Epoch Capabilities Index | — | 144.21 |
| ForecastBench | — | 60.5 |
Math Grok 4 Fast leads
Granite 3.1 8b Instruct: 30.4 (#210), Grok 4 Fast: 36.1 (#126)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Math | 1152 | 1419 |
Knowledge Too close to call
Granite 3.1 8b Instruct: 30.6 (#218), Grok 4 Fast: 31.5 (#211)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Expert | 1142 | 1411 |
| Vectara Hallucination Rate | — | 19.7% |
Multilingual Grok 4 Fast leads
Granite 3.1 8b Instruct: 31.1 (#255), Grok 4 Fast: 51.5 (#106)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Non-English | 1099 | 1397 |
| LMArena Chinese | 1145 | 1458 |
| LMArena Russian | 1092 | 1387 |
| LMArena French | — | 1433 |
| LMArena German | — | 1383 |
| LMArena Japanese | — | 1358 |
| LMArena Korean | — | 1359 |
| LMArena Spanish | — | 1414 |
Instruction Following Grok 4 Fast leads
Granite 3.1 8b Instruct: 58.9 (#254), Grok 4 Fast: 73.4 (#116)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Instruction Following | 1131 | 1388 |
Long Context Grok 4 Fast leads
Granite 3.1 8b Instruct: 35.2 (#236), Grok 4 Fast: 63.2 (#3)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Longer Query | 1162 | 1415 |
| Fiction.LiveBench | — | 94.4% |
Writing & Preference Grok 4 Fast leads
Granite 3.1 8b Instruct: 35.7 (#261), Grok 4 Fast: 60.2 (#96)
| Benchmark | Granite 3.1 8b Instruct | Grok 4 Fast |
|---|---|---|
| LMArena Text | 1150 | 1407 |
| LMArena Creative Writing | 1129 | 1388 |
| LMArena Multi-Turn | 1108 | 1414 |
Frequently asked questions
Is Granite 3.1 8b Instruct better than Grok 4 Fast?
Grok 4 Fast is the stronger model overall, scoring 39.0 to 31.8 on the Noometry Index.
Is Granite 3.1 8b Instruct or Grok 4 Fast better for coding?
Granite 3.1 8b Instruct scores higher on coding benchmarks: 33.9 versus 32.3 in the Noometry coding category.
How many benchmarks do Granite 3.1 8b Instruct and Grok 4 Fast share?
12 benchmarks have published results for both models. Granite 3.1 8b Instruct has 13 scored results on Noometry and Grok 4 Fast has 30.