  Sub-millisecond pulsars should be triaxial (Jacobi ellipsoids), which may not
spin down to super-millisecond periods via gravitation wave radiation during
their lifetimes if they are extremely low mass bare strange quark stars. It is
addressed that the spindown of sub-millisecond pulsars would be torqued
dominantly by gravitational wave radiation (with braking index n ~ 5). The
radio luminosity of sub-millisecond pulsars could be high enough to be detected
in advanced radio telescopes. Sub-millisecond pulsars, if detected, should be
very likely quark stars with low masses and/or small equatorial ellipticities.
