You can actually show different speeds in different terminals - the speed of terminal rendering affects the duration of the test. In the tests below, I have no custom terminal prompts or similar (no git status lines etc) - they're all distribution defaults running bash.

    # all the below run in the same MATE desktop
    # lxterm (from lxde - is easiest on my eye)
    $ time ls -R /usr
    real    0m19.974s
    user    0m0.860s
    sys	    0m0.832s

    # gnome terminal
    $ time ls -R /usr
    real    0m19.902s
    user    0m0.800s
    sys     0m0.776s

    # xterm (yes, it really is 10x the speed)
    $ time ls -R /usr
    real    0m1.872s
    user    0m0.856s
    sys     0m0.800s

    # rerun in the first terminal, and the time hasn't changed - still 19s

    # now in lxterm redirecting to null
    # (and xterm gives similar results here)
    $ time ls -R /usr > /dev/null

    real    0m0.418s
    user    0m0.256s
    sys     0m0.156s

All that prettification and rendering takes time; if you want raw speed, use xterm... or pipe output to /dev/null.

Interestingly, 'time' on gterm and lxterm had tabs between the above field:value pairs (I had to reformat to show them nicely), but xterm used spaces. I don't know enough about the terminal underpinnings to guess as to why.

All valid points, but (anecdotally) over the past several years of work, this holds true.