Reverse Time Migration (RTM) has become the standard for high-quality imaging in the seismic industry. RTM relies on PDE solutions using stencils that are 8th order or larger, which require large-scale HPC clusters to meet the computational demands. However, the rising power con- sumption of conventional cluster technology has prompted investigation of architectural alternatives that other higher computational efficiency. In this work, we compare the performance and energy efficiency of three architectural alternatives - the Intel Nehalem X5530 multicore processor, the NVIDIA Tesla C2050 GPU, and a general-purpose manycore chip design optimized for high-order wave equations called "Green Wave". We have developed an FPGA-accelerated architectural simulation platform to accurately model the power and performance of the Green Wave design. Results show that across highly-tuned high-order RTM stencils, the Green Wave implementation can offer up to 8× and 3.5× energy efficiency improvement per node respectively, com- pared with the Nehalem and GPU platforms. These results point to the enormous potential energy advantages of our hardware/software co-design methodology. Copyright 2011 ACM.