Before revision: 250px|upright=1.4|A comparison between single data rate, double data rate, and quad data rate upright=1.4|In QDR, the data lines operate at twice the frequency of the clock signal.
After revision: 250px|250px|upright=1.4|A comparison between single data rate, double data rate, and quad data rate upright=1.4|In QDR, the data lines operate at twice the frequency of the clock signal.