{"slug": "stepfun-step-5-preview-llm-on-aa-pareto-frontier", "title": "Stepfun Step 5 Preview (LLM): On AA Pareto frontier", "summary": "StepFun released Step 5 Preview on September 18, 2026, a reasoning model that scores 44 on the Artificial Analysis Intelligence Index, well above the median of 25 for comparable models. Step 5 Preview accepts text and image input, outputs text, has a 1M-token context window, and is priced at $1.00 per 1M input tokens and $2.70 per 1M output tokens, versus medians of $1.88 and $10.00. Evaluating the model on the Intelligence Index cost $918.34 and generated 160M tokens, compared with a median of 90M.", "body_md": "# Step 5 Preview Intelligence, Performance & Price Analysis\n\n### Model summary\n\n#### Speed\n\nStep 5 Preview is amongst the leading models in intelligence and well priced when comparing to other models of similar price. The model supports text and image input, outputs text, and has a 1M tokens context window.\n\nStep 5 Preview scores 44 on the Artificial Analysis Intelligence Index, placing it well above average among comparable models (median: 25). When evaluating the Intelligence Index, it generated 160M tokens, which is very verbose in comparison to the median of 90M.\n\nPricing for Step 5 Preview is $1.00 per 1M input tokens (competitively priced, median: $1.88) and $2.70 per 1M output tokens (competitively priced, median: $10.00). In total, it cost $918.34 to evaluate Step 5 Preview on the Intelligence Index.\n\n| Reasoning | Yes This page shows the reasoning version of this model. A non-reasoning variant may also exist. | \n|---|---|\n| Input modality | Supports: text and image | \n| Output modality | Supports: text | \n| Context window | 1M ~1500 A4 pages of size 12 Arial font | \n\nMetrics are compared against models of the same class:\n\n- Non-reasoning models → compared only with other non-reasoning models\n- Reasoning models → compared across both reasoning and non-reasoning\n- Open weights models → compared only with other open weights models of the same size class:\n- Tiny: ≤4B parameters\n- Small: 4B–40B parameters\n- Medium: 40B–150B parameters\n- Large: >150B parameters\n- Proprietary models → compared across proprietary and open weights models of the same price range, using a blended 3:1 input/output price ratio:\n- <$0.15 per 1M tokens\n- $0.15–$1 per 1M tokens\n- >$1 per 1M tokens\n\nHighlights\n\n### Speed\n\n## IntelligenceUpdated\n\n### [Artificial Analysis Intelligence Index](https://artificialanalysis.ai/evaluations/artificial-analysis-intelligence-index)\n\n### Artificial Analysis Intelligence Index by Open Weights / Proprietary\n\nMeasures the performance of models on specific capabilities and industries\n\n### [Artificial Analysis Finance & Accounting Index](https://artificialanalysis.ai/models/capabilities/finance-and-accounting)\n\n### Intelligence Evaluations\n\nAgentic knowledge work, (Elo-500)/2000\n\nAgentic real-world work tasks, (Elo-500)/2000\n\n[AutomationBench-AA](https://artificialanalysis.ai/evaluations/automationbench-aa)Updated\n\nAgentic SaaS workflows\n\nAgentic coding & terminal use\n\nCoding\n\nReasoning & knowledge\n\n[GDP.pdf](https://artificialanalysis.ai/evaluations/gdp-pdf)New\n\nProfessional document reasoning, All-pass\n\nPhysics reasoning\n\nKnowledge\n\n1 - hallucination rate\n\nLong context reasoning\n\nLegal agentic work, criterion pass rate\n\nAgentic business operations\n\nQuantitative analysis on spreadsheets & documents\n\nAgentic tool use\n\nKubernetes incident root-cause analysis\n\nVisual reasoning\n\n[MLCR-AA](https://artificialanalysis.ai/evaluations/mlcr-aa)New\n\nMedical long context reasoning\n\n### AA-Briefcase\n\n### AA-Briefcase Elo\n\n### AA-Omniscience\n\n### AA-Omniscience Index\n\n## Intelligence Index Comparisons\n\n### Intelligence Index vs. Cost per Intelligence Index Task\n\n## Token Use\n\n### Output Tokens per Intelligence Index Task\n\n## Cost\n\n### Cost per Intelligence Index Task\n\n### Cost to Run Artificial Analysis Intelligence Index\n\n### Pricing: Cache Hit, Input, and Output\n\n## Context Window\n\n### Context Window\n\n## Frequently Asked Questions\n\nCommon questions about Step 5 Preview\n\nStep 5 Preview was released on September 18, 2026.\n\nStep 5 Preview was created by StepFun.\n\nStep 5 Preview scores 44 on the Artificial Analysis Intelligence Index, placing it well above average among other reasoning models in a similar price tier (median: 25).\n\nStep 5 Preview costs $1.00 per 1M input tokens (very competitive, median: $1.88) and $2.70 per 1M output tokens (very competitive, median: $10.00), based on StepFun's API.\n\nStep 5 Preview costs $1.00 per 1M input tokens and $2.70 per 1M output tokens (based on StepFun's API). For a blended rate (7:2:1 cache hit/input/output ratio), this is $0.51 per 1M tokens. Pricing may vary by provider. [Compare provider pricing](https://artificialanalysis.ai/models/step-5/providers)\n\nWhen evaluated on the Intelligence Index, Step 5 Preview generated 160M output tokens, which is at the higher end compared to other reasoning models in a similar price tier (median: 90M).\n\nYes, Step 5 Preview is a reasoning model. It uses extended thinking or chain-of-thought reasoning to work through complex problems before providing an answer.\n\nStep 5 Preview supports text and image input.\n\nStep 5 Preview supports text output.\n\nYes, Step 5 Preview supports image input and can analyze, describe, and answer questions about images.\n\nYes, Step 5 Preview is multimodal. It can process text and image input and generate text output.\n\nStep 5 Preview has a context window of 1.0M tokens. This determines how much text and conversation history the model can process in a single request.\n\nNo, Step 5 Preview is proprietary. The model weights are not publicly available.\n\nStep 5 Preview has 600 billion parameters.\n\nStep 5 Preview achieves a score of 44 on the Artificial Analysis Intelligence Index. This composite benchmark evaluates models across reasoning, knowledge, mathematics, and coding.\n\nYes, Step 5 Preview is available via API through 1 provider. [Compare API providers](https://artificialanalysis.ai/models/step-5/providers)\n\nStep 5 Preview is available through 1 API provider. [Compare providers](https://artificialanalysis.ai/models/step-5/providers)", "url": "https://wpnews.pro/news/stepfun-step-5-preview-llm-on-aa-pareto-frontier", "canonical_source": "https://artificialanalysis.ai/models/step-5", "published_at": "2026-09-19 05:42:31+00:00", "updated_at": "2026-09-19 05:54:32.603371+00:00", "lang": "en", "topics": ["large-language-models", "ai-research", "ai-products"], "entities": ["StepFun", "Step 5 Preview", "Artificial Analysis Intelligence Index"], "alternates": {"html": "https://wpnews.pro/news/stepfun-step-5-preview-llm-on-aa-pareto-frontier", "markdown": "https://wpnews.pro/news/stepfun-step-5-preview-llm-on-aa-pareto-frontier.md", "text": "https://wpnews.pro/news/stepfun-step-5-preview-llm-on-aa-pareto-frontier.txt", "jsonld": "https://wpnews.pro/news/stepfun-step-5-preview-llm-on-aa-pareto-frontier.jsonld"}}