Processor networks connected by buses have attracted considerable attention. Since a reconfigurable array is more powerful than a PRAM and more practical, it becomes the focus of attention. The Processor Array with Reconfigurable Bus System (PARBS) and the Reconfigurable Multiple Bus Machine (RMBM) are both models of parallel computation based on reconfigurable bus and processor array. The PARBS is a processor array that consists of processors arranged to a 2-dimensional grid with a reconfigurable bus system. The RMBM is also made of processors and reconfigurable bus system, but the processors are located in a row and the number of processors and the number of buses are independent of each other. Four versions of RMBM has been proposed and Extended RMBM (E-RMBM) is regarded as the most powerful one among them. In this paper, we describe that a PARBS of size N M can be simulated in constant time by a E-RMBM of 4NM processors, M + 3 buses and 1 read buffer, and that a E-RMBM of P processors, B buses and D read buffers can be also simulated in constant time by a PARBS of size B P. A PARBS or RMBM that solves a computational problem of size n is polynomially bounded iff the product of the number of processors and buses and red and write ports is O (nc), for some constant c. When a PARBS is polynomially bounded, the E-RMBM which simulates it is also polynomially bounded, and vice versa.