Аннотация:We show that it is significant to take into account the architecture of computer processor and computer platform features to achieve a maximal performance of computer code at parallel computing. With this aim we examine several processor designs, which are used in high-performance computing systems of our faculty. Two problems (SHG-second harmonic generation and laser plume expansion) are chosen as a benchmark. For these problems the optimization technique for a single processor is examined, and the advantages of using the libraries are compared. In some cases the computation reorganization is necessary to take a full advantage of memory hierarchies. Full speedup of computation due to optimizations, suggested at executing in sequential mode of computer code, grows up to 8 times for Intel architectures of computer and up to 5.5 times for IBM architecture of computer.We discuss also using shared memory at parallel computing the SHG problem. We find out the way for overcoming the performance degradation with increasing a number of processors