This paper presents an innovative tool used during the verification of the UltraSPARC #IIIi (TM) processor. UltraSparc #IIIi operates in a multi-processor environment. Verifying the robustness of the cache coherency maintaining parts of the design was one of the main challenges facing the functional verification team. The team adopted a combination of standard, “classic” techniques and methodologies, as well as some new innovative approaches. This mixture of old and new led to a well-balanced, robust verification flow which enabled finding the majority of the design problems (bugs) early in the pre-silicon stage of the project. This paper discusses an internal tool (Sniper) (patent pending) which increases the processor bus activity in a way which would uncover subtle coherency problems.