OpenAI API vs Anthropic API

Claude Opus 5.5 leads the current AA Intelligence Index, 58 to 55, and output speed, 98.3 to 79.3 tokens/s. GPT-6.1 Sol has the lower illustrated request cost: $0.03 versus $0.06.

Updated · 4 sources · Methodology

DimensionWinnerMarginEvidence
SciCode (%)Claude Opus 5.512.73 ppGPT-6.1 Sol 54.17% / Claude Opus 5.5 66.90%12
Intelligence IndexClaude Opus 5.53 pointsGPT 55 / Claude 58
Output speed (tokens/s)Claude Opus 5.519.0 tokens/sGPT 79.3 / Claude 98.3 tokens/s
Illustrated request costGPT-6.1 Sol$0.03000GPT-6.1 Sol $0.03 / Claude Opus 5.5 $0.06

Model capabilities and output performance

ModelSciCode (%)AA v5 Intelligence IndexOutput speed (tokens/s)AA time to first answer token (s)
GPT-6.1 Sol154.175579.3251.44
Claude Opus 5.5266.905898.3687.99

Prices and request cost

ProviderInput / 1M tokensOutput / 1M tokensContext window (tokens)Max output (tokens)
GPT-6.1 Sol3$2$101,050,000128,0003
Claude Opus 5.54$4$201,000,000128,0004
Product documentationOpenAI API documentationAnthropic API documentation
Cost example: 10,000 input + 1,000 billed output tokens
GPT-6.1 Sol$0.03
Claude Opus 5.5$0.06

Capabilities and serving conditions

DimensionGPT-6.1 SolClaude Opus 5.5
Compared modelGPT-6.1 SolClaude Opus 5.5
Context / output limit1,050,000 / 128,000 tokens31,000,000 / 128K tokens4
Tool-calling constraintsGPT-6.1 Sol uses Responses for tool calling; Chat Completions is supported without tools.3Claude Opus 5.5 uses adaptive thinking that cannot be disabled; forced tool use returns an error.4

When each option fits

GPT-6.1 Sol (Max)

  • Choose GPT-6.1 Sol for an AA Intelligence Index of 55, output speed of 79.3 tokens/s and a $0.03 request example; the listed context capacity is 1,050,000 tokens.13

Claude Opus 5.5 (Max, Default Fallback)

  • Choose Claude Opus 5.5 for an AA Intelligence Index of 58, output speed of 98.3 tokens/s and a $0.06 request example; the listed context capacity is 1,000,000 tokens.24

Methodology and sources

SciCode is AA’s scientific-coding evaluation, reported as a percentage; higher is better. It is separate from the 10,000-input-token performance test and is not an in-editor Cline evaluation. Quality and performance use the configurations shown beside the model names. A current AA v5 Intelligence Index is displayed only where both models have a published value. AA performance uses the 10,000-input-token benchmark at each model’s displayed configuration; reasoning settings vary by model. Output speed is the median output rate. Answer latency measures the first answer token after reasoning, not the initial streamed reasoning chunk. For non-streamed reasoning and non-reasoning models, AA reports the same first-chunk and first-answer event. AA estimates answer latency from initial response and reasoning duration; it is not a separately sampled median. These are reference deployments, not Novita endpoint guarantees. The uncached cost example bills 10,000 input and 1,000 output tokens at each named seller’s tariff; it is not the cost of the AA benchmark. Prices, context and output limits use the cited seller sources.

  1. Artificial Analysis · GPT-6.1 Sol (Max) · quality and performance
  2. Artificial Analysis · Claude Opus 5.5 (Max, Default Fallback) · quality and performance
  3. OpenAI · GPT-6.1 Sol · API pricing and limits
  4. Anthropic · Claude Opus 5.5 · API pricing and limits

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