In modern computer systems the performance is dominated by the memory performance. Currently, there is neither a systematic design methodology nor a tool for the design of memory systems for general purpose computers.We present a first approach to CAD support for this crucial subtask of system level design. Dependencies between influencing factors and design decisions are explicitly represented by constraints and constraint logic programming is used to make the desing decisions. The memory design is optimized with respect to several objectives by iterating the (re)design cycle. Event driven simulation is used for evaluation of the intermediate results. The system is organized as an interactive design assistant.