In this paper the authors present FAST-GP, a framework for functional verification of RTL designs, which is based on fault injection and parallel simulation on GP-GPUs. Given a fault model, the framework translates the RTL code into an injected C code targeting NVIDIA GPUs, thus allowing a very fast parallel automatic test pattern generation and fault simulation. The paper compares different configurations of the framework to better exploit the architectural characteristics of such GPGPUs (such as thread synchronization, branch divergence, etc.) by considering the architectural characteristics of the RTL design under verification (i.e., complexity, size, number of injected faults, etc.).