The exemplary embodiments described herein relate to supporting fast and deterministic execution and simulation in multi-core environments. Specifically, the exemplary embodiments relate to systems and methods for implementing determinism in a memory system of a multithreaded computer. A exemplary system comprises a plurality of processors within a multi-processor environment, a cache memory within the processor and including metadata, and a hardware check unit performing one of a load check and a store check on the metadata to detect a respective one of a load metadata mismatch and a store metadata mismatch, and invoking a runtime software routine to order memory references upon a detection of one of the load metadata mismatch and the store metadata mismatch.