Cool Mega Array (CMA) is an energy efficient reconfigurable accelerator consisting of a large PE array with combinatorial circuits and a small microcontroller. In order to enhance the energy efficiency of the total system, a coprocessor design of CMA(Cool Mega Array), called CMA-Geyser is proposed. By replacing the programmable microcontroller by the host processor Geyser with a dedicated hardware controller, the setting up for the CMA and data transfer can be efficiently done. The design using 65nm CMOS process is compared with offloading style multicore system Cube-1. By eliminating the data memory and routers required in Cube-1, CMA-Geyser reduced 24.8% semiconductor area. By reducing both execution time and average power consumption, CMA-Geyser achieved about 3.4 times energy efficiency of Cube-1.