The development of a Computer System Architecture App provides the content of the lectures so that it is easier for the students to study even without aid from the lecturers. This app will assist self- directed learning tools. The Computer System Architecture course is compulsory in Semester 1 for the Diploma of Information Technology (Digital Technology) – DDT students in Politeknik Mersing. Before this, the students were taught only by use of PowerPoint slides which tended to be boring and unexciting. Students did not feel encouraged to understand the lecture. Therefore, the Computer System Architecture App was developed to help the students to more readily understand the material. The menu of the App consists of Notes, Quiz, Video, Games and a Calculator. With the multi approaches used in this app the interest of the students to study is enhanced. Response from the students indicated that this method was effective to enhance their understanding. The teaching duration was found to be shorter for the students to gain an understanding of the subject when aided by the Computer Architecture System App compared to the previous teaching method.