GPT-5.6 Sol and Luna outperform Terra in intelligence and cost efficiency analysis
New analysis shows GPT-5.6 Sol and Luna variants offer superior intelligence and cost efficiency compared to the Terra model.
1. Performance Comparison
Artificial Analysis released a report on July 13, 2026, comparing the intelligence and cost efficiency of the GPT-5.6 model variants: Sol, Terra, and Luna. According to the analysis, all three models represent an improvement over the previous GPT-5.5 iteration across reasoning tasks. When plotted on the Intelligence Index against the cost per task, the Sol and Luna variants consistently outperform Terra.
2. Efficiency Findings
The data indicates that for any given level of effort provided by the Terra model, users can achieve either higher intelligence at the same cost or equal intelligence at a lower cost by utilizing the Sol or Luna variants. Consequently, Sol and Luna maintain a superior position on the Pareto frontier. Among the three, GPT-5.6 Luna is highlighted as the most cost-efficient option for users balancing performance requirements with operational expenses.