The past decade has witnessed advances in computer architectures that have provided more speed and performance with memory than ever before. Real time processing for medical applications is approaching reality with these new hardware implementations. It becomes essential to investigate these architectures in light of present and possible future Picture Archiving and Communication Systems (PACS) requirements. We have chosen four possible architectures that represent the breadth of the present multi-processor systems. Actual and simulated timing results for performing a 2-Dimensional Fast Fourier Transform are presented. We then discuss how to evaluate candidate architectures.