This paper describes a first order multicore model to project a tighter upper bound on performance than previous Amdahl's Law based approaches. The speedup over a known baseline is a function of the core performance, microarchitectural features, application parameters, chip organization, and multicore topology. The model is flexible enough to consider both CPU and GPU like organizations as well as modern topologies from symmetric to aggressive heterogeneous (asymmetric, dynamic, and fused) designs. This extended model incorporates first order effect exposing more bottlenecks than previous applications of Amdahl's Law while remaining simple and flexible enough to be adapted for many applications.