Dynamic Binary Modification (DBM) is an important technique used in computer architecture simulators, virtualization, and program analysis, to name a few examples. The software ecosystem of RISC-V is maturing at pace, but is still missing a high-performance, optimized DBM. Addressing this requirement is key to improving the overall software ecosystem.This paper presents a comprehensive performance evaluation study for a DBM (MAMBO) which has been ported and optimized for 64-bit RISC-V. The main optimizations for DBM on RISC architectures have been implemented and tuned for RISC-V to address specific architectural features. For example, jump trampolines have been specifically developed to address the short direct branch range specified by the RISC-V ISA.The evaluation shows that for SPEC CPU2006 the geometric mean overhead is of 14.5%, with SPECint having the largest contribution with a geometric mean of 28.5%, while SPECfp has only an overhead of 5.6%. Concretely, this results in a reduction in runtime for h264ref from over 75 hours using the baseline DBM, to 2.2 hours with optimizations applied.