DDR memory requires precise and accurate power with high resolution control. As DDR4 comes on line the voltages will drop as process geometries do and accuracies will be even more demanding. To save power, frequency power scaling or changing the voltages to the memory depending on the frequency of the system operation are becoming more commonplace. The requirements for sequencing and rules based voltage application is critical for proper operation and to avoid errors or damage to the memory itself. When DDR memory is connected to other VLSI devices to utilize the memory, proper sequencing and control is needed. Accurate rails are needed for powering and termination as well. Several energy saving methods are used with memory including changing the voltage vs. clock speed as previously mentioned. Other methods are retention modes which involve powering the voltage down to a retention level and stopping the clock.