glebd

Gemini and Decloner compare files based on their content, so different file names don't matter. This is also why using just Spotlight for finding duplicates is very inaccurate. You may find similarly named files, but there won't be any guarantee that they are really identical; and you will also miss duplicate files that are named differently.

Our app Decloner (decloner.com) has a full-featured free 30-day trial period, you could give it a try.