Startup Doubler is a software acceleration program that compensates for sub-optimal disk performance to make extensions, control panels, the Finder and startup apps load faster. On average, it makes the startup process of you Mac 10-20% faster.
Version 2.7.3 fixes a freeze bug that would sometimes happen when the *Startup Doubler Extension grew larger than 500K. This version is also slightly faster than previous ones.
System 7.0 - 9.2.2.