Latency in QDR II compared to QDR

Question: Why is there an extra 1/2 clock cycle of latency on the QDR II compared to QDR?



The QDR II has an internal DLL(Delay Locked loop) which is used to make the TCO(Clock to output time) shorter on the QDR II and hence the extra 1/2 cycle of latency on the initial read. Thus increasing the data valid window.