Computer limitations and capabilities are purely controlled by programming, user input and current advances in computer technology that limit hardware. The main limit to computers is that user input is needed for the performance of tasks because computers are not self-actualizing. Self-actualization is necessary in achieving artificial intelligence.
Until self-actualizing computers are perfected, there will always be limitations on a computer's capabilities. Each piece of hardware has its own limitations that sets boundaries on what the computer can do. For example, a graphics card on a computer is limited by its architecture, no matter how capable the central processing unit may be.