hi! im new! My first impression was a little bad, but after i set the frameskip 0 i love it!(sorry for the bad english)
Well in  my machine(1000 Mhz celeron, 386 MB ram, mx 440) it worked 1-3 fps, and after i modifided it  go 10-15 fps! O yeah about the sound off switching thing: i dont really need it! the frame rate not changed in no sound or directsound, but it still blurred in few games!