The performance of a hypothetical multiprocessor back-end database machine is compared to that of a mainframe database system. The hypothetical database machine uses standard microprocessors and disks as well as processors and disks projected to be available in the future. The class of workloads considered is high-volume transaction processing. Analytic queueing models of the two architectures are constructed and used in parametric performance studies. The performance sensitivities with respect to transactions complexity, the amount of overhead required to implement the distributed database function, the amount of skew in the data access pattern, and the buffer miss ratio are determined.