In this paper, we describe TSOtool, a program to check the behavior of the memory subsystem in a shared memory multiprocessor. TSOtool runs pseudo-randomly generated programs with data races on a system compliant with the Total Store Order (TSO) memory consistency model; it then checks the results of the program against the formal TSO specification. Such analysis can expose subtle memory errors like data corruption, atomicity violation and illegal instruction ordering. While verifying TSO compliance completely is an NP-complete problem, we describe a new polynomial time algorithm which is incorporated in TSOtool. In spite of being incomplete, it has been successful in detecting several bugs in the design of commercial microprocessors and systems, during both pre-silicon and post-silicon phases of validation.