Question 1

What is the difference between Gemini 2.5 Flash Preview 05-20 (thinking) and Claude Opus 4?

Accepted Answer

Gemini 2.5 Flash Preview 05-20 (thinking) is developed by Google AI while Claude Opus 4 is developed by Anthropic. Gemini 2.5 Flash Preview 05-20 (thinking) has a 1.0M token context window vs Claude Opus 4's 200K. in 12 community votes on RIVAL, Claude Opus 4 wins 60% of head-to-head matchups. These results are based on blind head-to-head voting across 11 challenges.

Question 2

Which is better, Gemini 2.5 Flash Preview 05-20 (thinking) or Claude Opus 4?

Accepted Answer

Based on 12 community votes on RIVAL, Claude Opus 4 wins 60% of head-to-head matchups against Gemini 2.5 Flash Preview 05-20 (thinking). Claude Opus 4 is strongest in Web Design.

Question 3

How much does Gemini 2.5 Flash Preview 05-20 (thinking) cost compared to Claude Opus 4?

Accepted Answer

Gemini 2.5 Flash Preview 05-20 (thinking) costs $0.15/M input tokens and Claude Opus 4 costs $15/M input tokens. Gemini 2.5 Flash Preview 05-20 (thinking) is $14.85/M cheaper per input. The more expensive model wins 60% of duels, so the premium may be justified by quality.

Question 4

How are Gemini 2.5 Flash Preview 05-20 (thinking) vs Claude Opus 4 votes collected on RIVAL?

Accepted Answer

RIVAL presents both models' outputs side-by-side in blind duels — voters see the responses but don't know which model produced each one. This eliminates brand bias. 12 votes have been collected for this pair across 11 challenges. All vote data is part of RIVAL's open dataset.