The primary intention of this paper is to present the results of several cases where the FPGA technology was used for high performance calculations. We gathered applications that had been developed over the last couple of years. Over this period of time we observed that there had been a rapid growth of interest in the utilization of FPGA for HPC. Basing on our expertise we give selected metrics, results and conclusions which, in our opinion, are important for anyone who is interested in FPGA as an alternative for faster computations. A brief description of the characteristics of FPGA and FPGA usage for acceleration are also included for novices on the subject.