Algodoo

100 Rad/s reduced down to 0.1 Rad/s. Each gear halves the speed of the last, until you get 1/1000 of the original speed. Depending on which one you drive, you get an output of insane torque with no speed, or insane speed with no torque.

Runs at 25% realtime at 960Hz on my little no-power tablet laptop, so you shouldn't have trouble running it. If you do, just turn the frequency down a bit. You should only really need about 120Hz for it to run alright.

Made on my little no-power tablet laptop, just for full disclosure.