TopWinPrio Portable checks every now and then to see what window is active at the moment. When it finds the one, it gives it higher priority than the usual normal priority. Once this window loses focus, TopWinPrio Portable gives the window its standard status back. By default, TopWinPrio Portable gives the active application a priority "AboveNormal", but not "High" as many programs do. This is due to the balance of giving the active window a higher priority, meanwhile not taking priority from the drivers.