Source : WordNet®

overdrive
     n 1: the state of high or excessive activity or productivity or
          concentration; "Troops are ready to go into overdrive as
          soon as the signal is given"; "Melissa's brain was in
          overdrive"
     2: a high gear used at high speeds to maintain the driving
        speed with less output power
     v 1: drive or work too hard; "The teacher is overworking his
          students"; "Overdriving people often suffer stress"
     2: make use of too often or too extensively [syn: {overuse}]
     [also: {overdrove}, {overdriven}]

Source : Free On-Line Dictionary of Computing

Overdrive
     
         An {Intel} {Pentium} processor which fits into a
        socket designed to accomodate an {Intel 486}, or into a
        special upgrade socket on the {motherboard}.
     
        (1995-03-27)