I think that clock speed is very important for interstellar missions. Consider a machine intelligence travelling between the stars with the following parameters:

ship velocity = 7.8 AU/year
distace to Alpha Centauri = 271,923 AU (4.3 lightyears)
absolute flight time = 34,862 years
clock speed ratio = 1/14400 (1 subjective second every four absolute hours)
absolute processor speed = 208 kiloherz
subjective processor speed = 3 gigahertz
subjective travel time to Alpha Centauri = 883.6 days (2.42 years)

FASTER THAN LIGHT !!!! All because the machine intelligence slowed down its clock.

At this relatively low speed, it will be easier to protect the spacecraft from debris impacts, and who says repairs can't be carried out in ultra-slow-motion? Extremely low energy consumption is also an advantage, and may be possible using very subtle power sources.