I mean 10rpm, really! A 10" fan at 10rpm moves about as much air as a 2.5" fan at 160rpm.
You're not trying to move huge amounts of air, since heat transfer from the laptop to the air is pretty slow. You just need enough movement to clear out any hot air that is building up under the laptop.
> You just need enough movement to clear out any hot air that is building up under the laptop.
On a nearly totally different tangent, our own bodies build up hot pockets of air indoors as well, where there's no natural breeze to get rid of it. Getting rid of it creates a surprisingly strong cooling effect where you probably won't need AC for a while longer than you expect - and "air circulator" fans are pretty good at doing it over a whole room, so you don't need to keep a fan directed at yourself.
You're not trying to move huge amounts of air, since heat transfer from the laptop to the air is pretty slow. You just need enough movement to clear out any hot air that is building up under the laptop.