For fun, I just timed factor5 (the old version from 2009, I don't have newer) and it is about few
thousand times faster compared with the script (slow laptop, 6 threads in 2 cores to feed the cpu 100%, P95 running in background, i.e. doing nothing due to priority limit, computer still normally responsive).
Edit: that was for fun! TF on this exponent is totally pointless. Unless you consider yourself extremely lucky guy (like we Romanians would say, you stepped on a shit or put your hand in it, or one shit fell on your head, or
something).