Is my hardware good enough?

Hello. I'm currently attempting to play "Paper Mario: The Thousand Year Door", however I get inconsistent fps such as 38-55, however when I overlock i receive frames of over 80, my highest fps was 112

Here are my specs:
OS: Windows 7 Home Premium x64
Processor: Intel Core i5 650
Graphics Card: Nvidia GeForce GT 320
Ram: 6GB

If I have left anything out please inform me. Kind regards.