Due to the growing number of Chip-Multiprocessors, the researchers have proposed new designs and architectures. So, there is a constant need to know the most accurate simulators used in this scope, which should be used to identify their outcomes. Computer System Architecture (CSA) simulators are usually used to validate the designs, architectures that new discovered and developments. This paper is to provide an overview and insight into the most critical simulations used in Computer System Architecture and possible standards that distinguish simulators from the other. The essential aspects and parameters that determine these simulators are accuracy, speed, performance, flexibility, and functionality as well. Cycle-Accurate, Event-Driven and Full Systems Simulators of CSA, this taxonomy of simulators that w discusses in this paper.