Model comparison
Grok 4.1 Fast vs Grok 4.20 (Non-Reasoning)
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 5.7× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Last verified . 28 shared benchmarks.
Summary
- They share 28 benchmarks with published results for both. Grok 4.1 Fast scores higher in 2 categories and Grok 4.20 (Non-Reasoning) in 8 categories; 10 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Grok 4.20 (Non-Reasoning) leads 52.8 to 33.1.
- The biggest single-benchmark swing is ProofBench: 4% for Grok 4.1 Fast and 14% for Grok 4.20 (Non-Reasoning).
- Grok 4.1 Fast is cheaper at $0.20 / $0.50 per million input/output tokens, against $1.25 / $2.50 for Grok 4.20 (Non-Reasoning).
- Grok 4.20 (Non-Reasoning) accepts more context: 1M tokens versus 128K.
Side by side
| Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) | |
|---|---|---|
| Provider | xAI | xAI |
| Noometry Index | 41.4 | 48.6 |
| Released | 2025-06-27 | 2026-02-17 |
| Weights | Proprietary | Proprietary |
| Context window | 128K | 1M |
| Max output | 30K | 30K |
| Input $ / M tokens | $0.20 | $1.25 |
| Output $ / M tokens | $0.50 | $2.50 |
| Results tracked | 32 | 46 |
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Category by category
Coding Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 34.1 (#245), Grok 4.20 (Non-Reasoning): 42.1 (#112)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena WebDev | 1242 | 1375 |
| LMArena Coding | 1411 | 1459 |
| ALE-Bench | 394.93 | 1,150 |
| WeirdML | — | 52.3% |
Agentic & Tool Use Grok 4.1 Fast leads
Grok 4.1 Fast: 36.3 (#39), Grok 4.20 (Non-Reasoning): 34.4 (#46)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| τ²-bench Banking | 13.1% | 18% |
| LMArena Search | 1171 | 1189 |
| Vending-Bench 2 | 1,107 | 4,663 |
| Terminal-Bench | — | 57.3% |
| Berkeley Function Calling Leaderboard | 69.6% | — |
Reasoning Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 43.4 (#49), Grok 4.20 (Non-Reasoning): 52.3 (#32)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| NYT Connections (extended) | 87.4% | 85.4% |
| LMArena Hard Prompts | 1407 | 1451 |
| DTBench | 87.7% | 90.1% |
| ForecastBench | 61 | 61.4 |
| ARC-AGI-2 | — | 65.1% |
| SimpleBench | 56% | — |
| Kagi LLM Benchmark | — | 75% |
| ARC-AGI-1 | — | 89.5% |
| Chess Puzzles | — | 24% |
| Thematic Generalization | — | 63.8% |
| LMCA | — | 38.7% |
| Epoch Capabilities Index | — | 151.98 |
Math Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 31.9 (#221), Grok 4.20 (Non-Reasoning): 48.2 (#65)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| ProofBench | 4% | 14% |
| LMArena Math | 1408 | 1455 |
| FrontierMath (Tiers 1-3) | — | 44.9% |
| FrontierMath Tier 4 | — | 17.1% |
| MathArena Final-Answer Competitions | 60.9% | — |
| OTIS Mock AIME 2024-2025 | — | 92.2% |
Knowledge Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 33.1 (#207), Grok 4.20 (Non-Reasoning): 52.8 (#60)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Expert | 1399 | 1439 |
| GPQA Diamond | — | 89.3% |
| SimpleQA Verified | — | 30.2% |
| Vectara Hallucination Rate | 17.8% | — |
Multimodal Grok 4.1 Fast leads
Grok 4.1 Fast: 37.0 (#76), Grok 4.20 (Non-Reasoning): 33.3 (#98)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Vision | 1201 | 1263 |
| Blueprint-Bench 2 | — | 0% |
| LMArena Document | — | 1416 |
Multilingual Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 51.0 (#114), Grok 4.20 (Non-Reasoning): 54.5 (#40)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Non-English | 1391 | 1441 |
| LMArena Chinese | 1441 | 1481 |
| LMArena French | 1415 | 1476 |
| LMArena German | 1404 | 1465 |
| LMArena Japanese | 1349 | 1449 |
| LMArena Korean | 1361 | 1417 |
| LMArena Russian | 1387 | 1458 |
| LMArena Spanish | 1413 | 1443 |
Instruction Following Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 72.7 (#133), Grok 4.20 (Non-Reasoning): 74.8 (#83)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Instruction Following | 1376 | 1420 |
Long Context Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 42.4 (#126), Grok 4.20 (Non-Reasoning): 45.5 (#34)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Longer Query | 1390 | 1437 |
| CL-bench | — | 22.2% |
| CL-bench Life | — | 11.9% |
Writing & Preference Grok 4.20 (Non-Reasoning) leads
Grok 4.1 Fast: 57.2 (#131), Grok 4.20 (Non-Reasoning): 65.7 (#44)
| Benchmark | Grok 4.1 Fast | Grok 4.20 (Non-Reasoning) |
|---|---|---|
| LMArena Text | 1408 | 1451 |
| LMArena Creative Writing | 1394 | 1438 |
| EQ-Bench Creative Writing | 1327 | 1574 |
| LMArena Multi-Turn | 1389 | 1456 |
Frequently asked questions
Is Grok 4.1 Fast better than Grok 4.20 (Non-Reasoning)?
Grok 4.20 (Non-Reasoning) is the stronger model overall, scoring 48.6 to 41.4 on the Noometry Index. Grok 4.1 Fast costs 5.7× less per token, which makes it the better buy when Grok 4.20 (Non-Reasoning)'s lead doesn't matter for your workload.
Which is cheaper, Grok 4.1 Fast or Grok 4.20 (Non-Reasoning)?
Grok 4.1 Fast is cheaper. It lists at $0.20 per million input tokens and $0.50 per million output tokens; Grok 4.20 (Non-Reasoning) lists at $1.25 and $2.50.
Is Grok 4.1 Fast or Grok 4.20 (Non-Reasoning) better for coding?
Grok 4.20 (Non-Reasoning) scores higher on coding benchmarks: 42.1 versus 34.1 in the Noometry coding category.
Which has the bigger context window?
Grok 4.20 (Non-Reasoning) does, with 1M tokens against 128K.
How many benchmarks do Grok 4.1 Fast and Grok 4.20 (Non-Reasoning) share?
28 benchmarks have published results for both models. Grok 4.1 Fast has 32 scored results on Noometry and Grok 4.20 (Non-Reasoning) has 46.