We present a performance-based methodology for designing a high-bandwidth radar application on commodity platforms. Unlike many real-time systems, our approach works for commodity processors running commodity operating systems. Our technique is innovative because it uses stochastic models of the processing time at each step in the process to allow for the variabilities of running on a non-realtime operating system. We show how our system synthesizes the runtime parameters for a synthetic aperture radar application under a variety of loading conditions.