供电电压标准不同，参见：
Because power consumption increases with speed, the reduced voltage allows higher speed operation without unreasonable power and cooling requirements.
DDR4 operates at a voltage between 1.2 V and 1.4 V with a frequency between 800 and 2133 MHz (DDR4-1600 through DDR4-4266), compared to frequencies between 400 and 1067 MHz and voltage requirements of 1.5 or 1.65 V of DDR3. Due to the nature of DDR, speeds are typically advertised as doubles of these numbers (DDR3-1600 and DDR4-2400 are common, with DDR4-3200 and DDR4-4800 available at high cost). Although a low-voltage standard has yet to be finalized (as of August 2014), it is anticipated that low-voltage DDR4 will run at a voltage of 1.05 V, compared to DDR3's low-voltage standard (DDR3L) which requires 1.35 V to operate.
可查的有：
DDR3：1.5V；(DDR3最低工作电压1.5V，以下同理)
DDR3L：1.35V；
DDR3U：1.25V；
DDR4：1.2V；
DDR4L：1.05V。