  In recent years the more and more powerful GPU's available on the PC market
have attracted attention as a cost effective solution for parallel (SIMD)
computing. CUDA is a solid evidence of the attention that the major companies
are devoting to the field. CUDA is a hardware and software architecture
developed by Nvidia for computing on the GPU. It qualifies as a friendly
alternative to the approach to GPU computing that has been pioneered in the
OpenGL environment. We discuss the application of both the CUDA and the OpenGL
approach to the simulation of 2-d spin systems (XY model).
