The explosion of digital data and the high computation demands of data analysis have made the memory system a major contributor to the performance and power consumption of modern computing systems. Both industry and academia have proposed innovations such as new memory architectures, interfaces, devices, and topologies, that has lead to a vast increase in the design space of memory systems. In this paper, we present CramSim, which is a flexible, extensible, and scalable simulation framework designed to help effi- ciently explore the vast design space of memory systems. CramSim is designed on top of SST (Structural Simulation Toolkit) to decouple basic functional blocks of the memory system into separate components. This modular design eases modeling of individual components and evaluation of various con?gurations of memory systems.