Evo 2010-01-26 12:33:07 #1 A .SID file is actually a datafile containing a C64 program used to play the music or soundfx data contained in the same file. To play the file you will need the Playsid program for windows or Amiga. Playsid is a sort of an emulator which emulates the processor and the soundchip (Sound Interface Device, S.I.D.) to play the data. The windows version of the program is very accurate on the audio emulation. There's no audible difference with the real SID.