Nowadays we can find AC systems that have ratings up to 23 SEER which make them ultra high efficiency units. These systems require exceptional variable compressors that help maintain the optimal comfort level by turning on and off as little as often. The key to keep the same temperature without having to make those manual adjustments to your fan speed lies inside of the outdoor condenser and the indoor variable speed blower motor. The compressor of these high efficient units can variably control the flow of refrigerant and airflow going through your system.
The chart below helps to understand how temperature is maintained and the minimal amount of energy is used to keep the temperature consistent over long periods of time. See how much more energy a basic system consumes!