The amount of charge stored in an SRAM cell shrinks rapidly with each technology generation thus increasingly exposing caches to soft errors. Benchmarking the FIT rate of caches due to soft errors is critical to evaluate the relative merits of a plethora of protection schemes that are being proposed to protect against soft errors. The benchmarking of cache reliability introduces a unique challenge as compared to internal processor storage structures, such as the load/store queue. In the case of internal processor structures the time a data bit resides in the structure is so short that it is generally safe to assume that no more than one soft error strike can occur. Thus the reliability of such structures is overwhelmingly dominated by single bit errors. By contrast, a memory block may reside for millions of cycles in a last level cache. In this case it is important to consider the impact of the spatial and temporal distribution of multiple errors within the lifetime of a cache block i...