Where is Samsung SSD Magician Performance Benchmarks Stored?

Run a new benchmark. Then use the Find Files/Folders function in Windows to find all those files that were modified today.

For example, in Windows 98 go to Start -> Find -> Files or Folders, select the Date tab, and find all files Modified (or Created) during the previous 1 day.

Otherwise, if SSD Magician stores it stuff in your registry, then use a registry monitoring tool to track the changes. You can also track registry changes relatively easily without a special tool. Let me know if you need to do this.