We conducted a performance evaluation of a production supercomputer based on the Intel Xeon Processor E5-2680v4 (Broadwell), a fourteen-core die shrink of the Haswell architecture and compared and contrasted it with two earlier Xeons: the E5-2680v3 (Haswell), a twelve-core implementation of the fourth-generation Haswell architecture and the E5-2680v2 (Ivy Bridge), a ten-core die shrink of the third-generation Sandy Bridge architecture. The new features of Broadwell architecture are evaluated and compared with Ivy Bridge using several low-level benchmarks and five full-scale production quality scientific and engineering applications. A model to predict the performance of HPCG, Overflow and Cart3D is presented for two architectures. In addition, we evaluate the effects of degrading base core frequency to AVX frequency while using AVX2 instructions and of the Turbo Boost feature.