Gemini 4 Carbon vs Claude Fable 5.1: benchmarks and token cost

This comparison uses Gemini 4 Carbon (High) and Claude Fable 5.1 (Xhigh, Default Fallback). It reports the captured benchmark data, with no new hands-on test.

Carbon and Fable differ in both index and rate

Carbon’s captured intelligence index is 59.4 against Fable’s 49.7, and Carbon’s listed token rates are lower. The models also use different named effort settings, so the comparison should retain those variants rather than collapse the result into a general claim about either provider. Test representative prompts and output requirements before assigning a task-specific advantage.

How to read the table

The intelligence index is an aggregate measurement, not a percentage of correct answers in your application. Input and output prices are separate rates per million tokens. Coding and math indices are unavailable in this capture and must not be read as zero. Compare first-token latency separately from output-token throughput, and use the same model effort settings for a trial. Choose using task quality, total time and the cost of accepted results; provider features and deployment requirements need their own checks.