Model comparison
Claude Opus 4.8 vs Step 3
Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 40.5 on the Noometry Index.
Last verified . 17 shared benchmarks.
StepFunSummary
- They share 17 benchmarks with published results for both. Claude Opus 4.8 scores higher in 9 categories and Step 3 in 0 categories; 9 gaps are clear of the uncertainty.
- The widest gap is in math, where Claude Opus 4.8 leads 78.4 to 37.6.
- The biggest single-benchmark swing is Kagi LLM Benchmark: 88.8% for Claude Opus 4.8 and 62.3% for Step 3.
- Step 3 has downloadable open weights; the other is API-only.
Side by side
| Claude Opus 4.8 | Step 3 | |
|---|---|---|
| Provider | Anthropic | StepFun |
| Noometry Index | 60.7 | 40.5 |
| Released | 2026-05-28 | — |
| Weights | Proprietary | Open |
| Context window | 1M | — |
| Max output | 128K | — |
| Input $ / M tokens | $5 | — |
| Output $ / M tokens | $25 | — |
| Results tracked | 65 | 17 |
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Category by category
Coding Claude Opus 4.8 leads
Claude Opus 4.8: 59.9 (#12), Step 3: 40.1 (#147)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Coding | 1490 | 1367 |
| DeepSWE | 59% | — |
| FrontierCode | 46.5% | — |
| LMArena WebDev | 1556 | — |
| SciCode | 53.5% | — |
| GSO | 47.1% | — |
| WeirdML | 82.9% | — |
| ALE-Bench | 1,564 | — |
Agentic & Tool Use Not comparable
Claude Opus 4.8: 47.6 (#11), Step 3: —
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| APEX-Agents | 48.9% | — |
| OSWorld 2.0 | 20.6% | — |
| Remote Labor Index | 8.3% | — |
| τ²-bench Banking | 39.7% | — |
| DeepResearch Bench | 50.2% | — |
| PostTrainBench | 33.8% | — |
| GBAEval | 70.9% | — |
| GDP.pdf | 24% | — |
| LMArena Search | 1204 | — |
| Vending-Bench 2 | 5,787 | — |
Reasoning Claude Opus 4.8 leads
Claude Opus 4.8: 64.7 (#16), Step 3: 28.4 (#105)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| Kagi LLM Benchmark | 88.8% | 62.3% |
| LMArena Hard Prompts | 1482 | 1355 |
| ARC-AGI-2 | 72.1% | — |
| SimpleBench | 64.8% | — |
| NYT Connections (extended) | 91.1% | — |
| ARC-AGI-1 | 92.5% | — |
| CritPt | 20.9% | — |
| Chess Puzzles | 34% | — |
| EnigmaEval | 23.5% | — |
| EBR-Bench | 28.6% | — |
| Mystery Game Puzzles | 36% | — |
| DTBench | 94.9% | — |
| LMCA | 57.5% | — |
| Surface Evolver Bench | 87.5% | — |
| Bench to the Future 3 | 0.14 | — |
| Epoch Capabilities Index | 158.21 | — |
| ForecastBench | 59.9 | — |
Math Claude Opus 4.8 leads
Claude Opus 4.8: 78.4 (#13), Step 3: 37.6 (#148)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Math | 1487 | 1366 |
| FrontierMath (Tiers 1-3) | 80% | — |
| FrontierMath Tier 4 | 56.1% | — |
| MathArena Final-Answer Competitions | 91.8% | — |
| OTIS Mock AIME 2024-2025 | 98.3% | — |
| ProofBench | 69% | — |
| FrontierMath (Feb 2025 set) | 47.2% | — |
| FrontierMath Tier 4 (v1) | 31.3% | — |
Knowledge Claude Opus 4.8 leads
Claude Opus 4.8: 61.3 (#29), Step 3: 36.8 (#164)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Expert | 1502 | 1333 |
| GPQA Diamond | 91% | — |
| SimpleQA Verified | 53% | — |
Multimodal Claude Opus 4.8 leads
Claude Opus 4.8: 42.9 (#26), Step 3: 35.5 (#86)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Vision | 1294 | 1177 |
| Blueprint-Bench 2 | 14.5% | — |
| Furniture Assembly | 42.5% | — |
| LMArena Document | 1475 | — |
Multilingual Claude Opus 4.8 leads
Claude Opus 4.8: 55.2 (#33), Step 3: 46.3 (#159)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Non-English | 1450 | 1327 |
| LMArena Chinese | 1507 | 1397 |
| LMArena German | 1472 | 1371 |
| LMArena Korean | 1432 | 1269 |
| LMArena Russian | 1474 | 1331 |
| LMArena Spanish | 1466 | 1371 |
| LMArena French | 1481 | — |
| LMArena Japanese | 1440 | — |
Instruction Following Claude Opus 4.8 leads
Claude Opus 4.8: 77.4 (#24), Step 3: 70.4 (#164)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Instruction Following | 1476 | 1332 |
Long Context Claude Opus 4.8 leads
Claude Opus 4.8: 45.4 (#35), Step 3: 40.3 (#157)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Longer Query | 1483 | 1326 |
Writing & Preference Claude Opus 4.8 leads
Claude Opus 4.8: 72.0 (#16), Step 3: 54.3 (#151)
| Benchmark | Claude Opus 4.8 | Step 3 |
|---|---|---|
| LMArena Text | 1461 | 1350 |
| LMArena Creative Writing | 1454 | 1321 |
| LMArena Multi-Turn | 1476 | 1341 |
| EQ-Bench Creative Writing | 1840 | — |
| EQ-Bench 4 | 1281 | — |
Frequently asked questions
Is Claude Opus 4.8 better than Step 3?
Claude Opus 4.8 is the stronger model overall, scoring 60.7 to 40.5 on the Noometry Index.
Is Claude Opus 4.8 or Step 3 better for coding?
Claude Opus 4.8 scores higher on coding benchmarks: 59.9 versus 40.1 in the Noometry coding category.
How many benchmarks do Claude Opus 4.8 and Step 3 share?
17 benchmarks have published results for both models. Claude Opus 4.8 has 65 scored results on Noometry and Step 3 has 17.