The paper presents a comparative analysis of two power side-channel attacks, namely differential power analysis (DPA) and correlation power analysis (CPA), applied to the Advanced Encryption Standard (AES) algorithm. The objective is to assess the efficacy of these attacks on an asynchronous-logic masked AES accelerator, specifically designed to withstand power analysis attacks. The experiments are conducted using a meticulously constructed test platform that enabled the collection of power consumption data during the encryption process. The findings reveal that both DPA and CPA attacks successfully uncover the AES key, albeit CPA exhibits slightly superior effectiveness compared to DPA. Additionally, this study explores the impact of countermeasures, such as masking and shuffling, on the effectiveness of these attacks. The results unequivocally demonstrate that the implementation of these countermeasures substantially diminishes the effectiveness of DPA and CPA attacks. Overall, this study emphasizes the significance of deploying countermeasures to mitigate power-side channel attacks, while providing valuable insights into the relative effectiveness of DPA and CPA attacks on AES-128.