Remarkable!

    $ xz -9 --verbose jarvis.iso

    1,348.2 MiB / 7,600.0 MiB = 0.177   1.3 MiB/s    1:38:06

The file shrunk from 7.9GB to 1.4GB. But took 1 hour and 38 minutes to
compress... I hear decompression is even longer.