Model comparison
Grok 4.5 vs Step 5 Preview
Grok 4.5 is the stronger model overall, scoring 55.0 to 47.9 on the Noometry Index. Step 5 Preview costs 2.1× less per token, which makes it the better buy when Grok 4.5's lead doesn't matter for your workload.
Last verified . 18 shared benchmarks.
StepFunSummary
- They share 18 benchmarks with published results for both. Grok 4.5 scores higher in 8 categories and Step 5 Preview in 1 category; 5 gaps are clear of the uncertainty.
- The widest gap is in knowledge, where Grok 4.5 leads 62.3 to 41.2.
- The biggest single-benchmark swing is ProofBench: 31% for Grok 4.5 and 42% for Step 5 Preview.
- Step 5 Preview is cheaper at $1 / $2.70 per million input/output tokens, against $2 / $6 for Grok 4.5.
- Step 5 Preview accepts more context: 1.02M tokens versus 500K.
Side by side
| Grok 4.5 | Step 5 Preview | |
|---|---|---|
| Provider | xAI | StepFun |
| Noometry Index | 55.0 | 47.9 |
| Released | 2026-07-08 | 2026-09-16 |
| Weights | Proprietary | Proprietary |
| Context window | 500K | 1.02M |
| Max output | 500K | 66K |
| Input $ / M tokens | $2 | $1 |
| Output $ / M tokens | $6 | $2.70 |
| Results tracked | 52 | 18 |
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Category by category
Coding Too close to call
Grok 4.5: 52.2 (#35), Step 5 Preview: 51.8 (#36)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena WebDev | 1553 | 1564 |
| SciCode | 54.1% | 58.9% |
| LMArena Coding | 1474 | 1480 |
| DeepSWE | 53.8% | — |
| FrontierCode | 42.4% | — |
| WeirdML | 46.4% | — |
| ALE-Bench | 1,309 | — |
Agentic & Tool Use Not comparable
Grok 4.5: 44.4 (#17), Step 5 Preview: —
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| APEX-Agents | 56.2% | — |
| τ²-bench Banking | 47.9% | — |
| PostTrainBench | 23.4% | — |
| GBAEval | 65.4% | — |
| GDP.pdf | 14% | — |
| LMArena Search | 1213 | — |
| Vending-Bench 2 | 3,887 | — |
Reasoning Grok 4.5 leads
Grok 4.5: 56.1 (#25), Step 5 Preview: 40.0 (#57)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| CritPt | 15.4% | 20.9% |
| LMArena Hard Prompts | 1462 | 1465 |
| ARC-AGI-2 | 52.6% | — |
| SimpleBench | 70% | — |
| Kagi LLM Benchmark | 83.5% | — |
| NYT Connections (extended) | 79.9% | — |
| ARC-AGI-1 | 87.2% | — |
| Chess Puzzles | 36% | — |
| DTBench | 96.5% | — |
| LMCA | 45.2% | — |
| Surface Evolver Bench | 74.4% | — |
| Epoch Capabilities Index | 153.92 | — |
Math Grok 4.5 leads
Grok 4.5: 60.9 (#35), Step 5 Preview: 46.1 (#72)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| ProofBench | 31% | 42% |
| LMArena Math | 1459 | 1470 |
| FrontierMath (Tiers 1-3) | 57.2% | — |
| FrontierMath Tier 4 | 24.4% | — |
| OTIS Mock AIME 2024-2025 | 97.8% | — |
Knowledge Grok 4.5 leads
Grok 4.5: 62.3 (#24), Step 5 Preview: 41.2 (#112)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Expert | 1466 | 1470 |
| GPQA Diamond | 93.4% | — |
| SimpleQA Verified | 48.3% | — |
Multimodal Step 5 Preview leads
Grok 4.5: 37.6 (#72), Step 5 Preview: 41.0 (#41)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Vision | 1288 | 1267 |
| Blueprint-Bench 2 | 27.3% | — |
| Furniture Assembly | 22.5% | — |
| LMArena Document | 1452 | — |
Multilingual Too close to call
Grok 4.5: 54.4 (#42), Step 5 Preview: 53.8 (#54)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Non-English | 1440 | 1432 |
| LMArena Chinese | 1496 | 1519 |
| LMArena Russian | 1448 | 1436 |
| LMArena Spanish | 1450 | 1439 |
| LMArena French | 1456 | — |
| LMArena German | 1446 | — |
| LMArena Japanese | 1428 | — |
| LMArena Korean | 1404 | — |
Instruction Following Too close to call
Grok 4.5: 76.0 (#48), Step 5 Preview: 76.0 (#50)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Instruction Following | 1446 | 1444 |
Long Context Too close to call
Grok 4.5: 44.8 (#56), Step 5 Preview: 44.5 (#64)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Longer Query | 1463 | 1455 |
Writing & Preference Grok 4.5 leads
Grok 4.5: 65.8 (#42), Step 5 Preview: 62.8 (#71)
| Benchmark | Grok 4.5 | Step 5 Preview |
|---|---|---|
| LMArena Text | 1448 | 1442 |
| LMArena Creative Writing | 1442 | 1410 |
| LMArena Multi-Turn | 1456 | 1447 |
| EQ-Bench Creative Writing | 1579 | — |
Frequently asked questions
Is Grok 4.5 better than Step 5 Preview?
Grok 4.5 is the stronger model overall, scoring 55.0 to 47.9 on the Noometry Index. Step 5 Preview costs 2.1× less per token, which makes it the better buy when Grok 4.5's lead doesn't matter for your workload.
Which is cheaper, Grok 4.5 or Step 5 Preview?
Step 5 Preview is cheaper. It lists at $1 per million input tokens and $2.70 per million output tokens; Grok 4.5 lists at $2 and $6.
Is Grok 4.5 or Step 5 Preview better for coding?
They score almost the same on coding (52.2 vs 51.8); test both on your own repository before choosing.
Which has the bigger context window?
Step 5 Preview does, with 1.02M tokens against 500K.
How many benchmarks do Grok 4.5 and Step 5 Preview share?
18 benchmarks have published results for both models. Grok 4.5 has 52 scored results on Noometry and Step 5 Preview has 18.