Model comparison
Grok 4 Fast vs Step 2 16k Exp 202412
Grok 4 Fast and Step 2 16k Exp 202412 score almost the same on the Noometry Index (39.4 vs 39.2), so choose on price, context window or the category you care about most.
Last verified . 12 shared benchmarks.
StepFunSummary
- They share 12 benchmarks with published results for both. Grok 4 Fast scores higher in 5 categories and Step 2 16k Exp 202412 in 3 categories; 8 gaps are clear of the uncertainty.
- The widest gap is in long context, where Grok 4 Fast leads 63.2 to 39.7.
Side by side
| Grok 4 Fast | Step 2 16k Exp 202412 | |
|---|---|---|
| Provider | xAI | StepFun |
| Noometry Index | 39.4 | 39.2 |
| Released | 2025-09-19 | — |
| Weights | Proprietary | Proprietary |
| Context window | — | — |
| Max output | — | — |
| Input $ / M tokens | — | — |
| Output $ / M tokens | — | — |
| Results tracked | 30 | 12 |
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Category by category
Coding Step 2 16k Exp 202412 leads
Grok 4 Fast: 32.5 (#271), Step 2 16k Exp 202412: 38.5 (#174)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Coding | 1429 | 1316 |
| LMArena WebDev | 1159 | — |
| WeirdML | 42.9% | — |
Agentic & Tool Use Not comparable
Grok 4 Fast: 29.5 (#86), Step 2 16k Exp 202412: —
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| τ²-bench Banking | 15.7% | — |
| Cybench | 30% | — |
| LMArena Search | 1171 | — |
Reasoning Step 2 16k Exp 202412 leads
Grok 4 Fast: 22.2 (#201), Step 2 16k Exp 202412: 25.9 (#142)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Hard Prompts | 1412 | 1299 |
| ARC-AGI-2 | 5.3% | — |
| Kagi LLM Benchmark | 66.1% | — |
| ARC-AGI-1 | 48.5% | — |
| DTBench | 82.7% | — |
| Epoch Capabilities Index | 144.2 | — |
| ForecastBench | 60.5 | — |
Math Grok 4 Fast leads
Grok 4 Fast: 38.9 (#123), Step 2 16k Exp 202412: 36.3 (#169)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Math | 1419 | 1304 |
Knowledge Step 2 16k Exp 202412 leads
Grok 4 Fast: 32.0 (#214), Step 2 16k Exp 202412: 35.2 (#187)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Expert | 1411 | 1279 |
| Vectara Hallucination Rate | 19.7% | — |
Multilingual Grok 4 Fast leads
Grok 4 Fast: 51.3 (#111), Step 2 16k Exp 202412: 43.7 (#181)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Non-English | 1396 | 1290 |
| LMArena Chinese | 1457 | 1331 |
| LMArena Russian | 1389 | 1324 |
| LMArena French | 1431 | — |
| LMArena German | 1383 | — |
| LMArena Japanese | 1352 | — |
| LMArena Korean | 1357 | — |
| LMArena Spanish | 1415 | — |
Instruction Following Grok 4 Fast leads
Grok 4 Fast: 73.2 (#121), Step 2 16k Exp 202412: 67.9 (#192)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Instruction Following | 1387 | 1287 |
Long Context Grok 4 Fast leads
Grok 4 Fast: 63.2 (#3), Step 2 16k Exp 202412: 39.7 (#170)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Longer Query | 1415 | 1307 |
| Fiction.LiveBench | 94.4% | — |
Writing & Preference Grok 4 Fast leads
Grok 4 Fast: 60.0 (#102), Step 2 16k Exp 202412: 52.3 (#173)
| Benchmark | Grok 4 Fast | Step 2 16k Exp 202412 |
|---|---|---|
| LMArena Text | 1407 | 1321 |
| LMArena Creative Writing | 1387 | 1328 |
| LMArena Multi-Turn | 1414 | 1292 |
Frequently asked questions
Is Grok 4 Fast better than Step 2 16k Exp 202412?
Grok 4 Fast and Step 2 16k Exp 202412 score almost the same on the Noometry Index (39.4 vs 39.2), so choose on price, context window or the category you care about most.
Is Grok 4 Fast or Step 2 16k Exp 202412 better for coding?
Step 2 16k Exp 202412 scores higher on coding benchmarks: 38.5 versus 32.5 in the Noometry coding category.
How many benchmarks do Grok 4 Fast and Step 2 16k Exp 202412 share?
12 benchmarks have published results for both models. Grok 4 Fast has 30 scored results on Noometry and Step 2 16k Exp 202412 has 12.