For me, range (the posted source) took 95 seconds, and xrange was only a little better at 85 seconds. I think most of the benefit of xrange comes from the decr

For me, range (the posted source) took 95 seconds, and xrange was only a little better at 85 seconds. I think most of the benefit of xrange comes from the decreased memory usage, not from lower CPU usage. But xrange is definitely closer to what the other code is doing.