Attempt of unbiased comparison of GPU and CPU performance in common scientific computing

Graphics processing units (GPU) are considered to have superior performance over the central processing units (CPU) in performing common scientific computations. Number of factors that can seriously change this conception are usually overlooked. In this paper, some of these factors are taken into account and their impact is measured, analysed and discussed. Matrix multiplication and Shell sorting examples are used to show that GPU superiority is not always clear.