effective, timesaving, prompt, competent, expeditious, economical, businesslike, streamlined, economic, high-octane, more...

inefficient, wasteful, ineffective, unproductive, slow

energy-efficient, time-efficient, cost-efficient, water-efficient, space-efficient, resource-efficient, process-efficient, more...

least, most, energy, highest, cost, bandwidth, prime, active, external, poorest, highly

more effective,   works well,   very effective,   working well,   highly effective,   well oiled machine,   gets the job done,   wasting no time,   not time consuming,   more productive