In designing complex systems, a performance evaluation model is essential in determining a system configuration and identifying performance bottlenecks. Several C++-based general-purpose simulation tools such as systemC and CynLib have also been introduced. However, these tools are cycle-based, which simulates a system synchronously under the assumption that all modules are invoked even cycle, thus eliminating scheduling overhead in order;to simulate a system containing multiple clocks or asynchronous circuits with accuracy, an event-driven approach is highly desirable. We have developed an event-driven framework of computer system simulation in C++, called simCore, which is mainly targeted for performance evaluation simulation of computer systems, providing concurrent execution of multiple modules and event-driven module interaction mechanisms. However, in order to demonstrate its cycle-accuracy and high simulation speed, rye compared two MIPS-based system simulators, one bused on the C++-based event-driven simulation core and the other based on Verilog-XL.