1. An emulation system, comprising: a workstation; and an emulator coupled to the workstation and configured to implement a circuit emulation model for a circuit design, the circuit design having access to a memory, the memory being modeled with a main memory model in the workstation and a cache memory model in the emulator, the cache memory model storing a subset of data that are stored in the main memory model and being synchronized with the main memory model, the cache memory being a hardware model and the main memory model being a software model.