This document summarizes GPU performance tests of the RiverFlow2D hydraulic model. Four test cases using real river meshes demonstrate speedups of up to 680 times faster than the CPU version. Later generation GPUs like the Tesla V100 and RTX 2080 Ti outperform older GPUs. While the Tesla V100 is fastest, the GTX 1080 Ti offers remarkable acceleration at lower cost. GPU acceleration allows simulating larger domains with finer meshes that were previously impractical due to runtimes.