Despite of all hardware capabilities, optimization of software always was one of actual tasks. Usually optimization of software was aimed to reduce an execution time. But recent decades it’s possible sometimes also to reduce energy consumption and/or energy efficiency of computing because of enhanced energy saving capabilities. Indeed, if computations are made faster, CPU can suspend unusual computational and control blocks. In case of parallelization which is one of optimization techniques, power consumption can raise in short periods of computations because of using multiple CPUs simultaneously. At once execution time can be decreased dramatically so energy efficiency of computing still increasing. In the paper the authors provide the experiments on small size mini PC Raspberry Pi 3B which show that using of optimization tiling method not only speed up a processing but also increase energy efficiency of computing. For such low power systems this can be useful to increase power on time with a battery power source.