It takes a sequence of instructions to read the RAM. First, the ACTIVE command must be issued to the row containing the desired data. Then, READ commands can be issued to read data from the active row. Back-to-back READ commands can be performed, so that a continuous, uninterrupted flow of data from the active row can be supplied. Writes have similar operating characteristics to reads — they are initiated with the WRITE command, and continuous, uninterrupted writes can be performed on the selected row.
Corsair Explains Memory Latencies
Source: PC Perspective
Today Corsair has posted a PDF document on their website that explains the magic of memory latencies and how they affect performance. You can find it llsted under the “RAM Guy’s Topics” section on their homepage.