Active Messages is a versatile and efficient communication architecture that offers significant performance improvement over conventional message-passing approach. The Active Messages architecture achieves its efficiency by carefully integrating the hardware capabilities of the underlying machine with the software layers above it. By taking a minimalistic approach, each Active Messages primitive is highly optimized and therefore its performance is sensitive to the particular design choices being made. In this report, we compare the performance of two implementations of Active Messages on the CM-5, CMAM version 2.7 and CMAML in CMMD version 3.1.final, and investigate how the design trade-offs affect the performance of the different Active Message functions. At the same time, we also develop a new benchmark framework that can be applied to measure the performance of message passing libraries in general.