However, the faster RAM is, the better. Most chips today operate with a cycle rate of 50 to 70 nanoseconds. We will talk about these various types of memory later. System RAM speed is controlled by Bus width and bus speed . Bus width refers to the number of bits that can be sent to the CPU simultaneously, and bus speed refers to the number of times a group of bits can be sent each second.
Latency refers to the number of clock cycles needed to read a bit of information.
To compensate for latency, CPUs uses a special technique called burst mode . Burst mode depends on the expectation that data requested by the CPU will be stored in sequential memory cells. The memory controller anticipates that whatever the CPU is working on will continue to come from this same series of memory addresses, so it reads several consecutive bits of data together. The rated burst mode of memory is normally expressed as four numbers separated by dashes. The first number tells you the number of clock cycles needed to begin a read operation, the second, third and fourth numbers tell you how many cycles are needed to read each consecutive bit in the row, also known as the wordline .