The Von Neumann architecture is a computer design model that uses a single memory space for both instructions and data. This means that the CPU fetches instructions and data from the same memory, which can lead to bottlenecks when both are accessed simultaneously. In contrast, the Harvard architecture features separate memory spaces for instructions and data. This allows the CPU to access instructions and data at the same time, improving performance in certain applications. Each architecture has its advantages, with Von Neumann being simpler and more flexible, while Harvard can be faster for specific tasks.