What is CAS Latency and how does it work?
CAS Latency (also referred to as CL or simply latency) is the amount of time it takes for your memory to respond to a command. Specifically, it is the length of time between memory receiving a command to read data, and the first piece of data being output from memory. Latency is measured in terms of clock cycles and is often noted as CL2 (two clock cycles) or CL3 (three clock cycles). CL2 parts process data a little quicker than CL3 parts as it takes one clock cycle less for the initial data to be processed. However, after the first piece of data is processed, the rest of the data is processed at equal speeds. Latency only affects the initial burst of data. Once data starts flowing, there is no difference in processing speed. Please note, a clock cycle for a PC100 module is 10 nanoseconds so you probably won’t notice a significant performance difference. Most systems will accept either latency part. However, there are some systems that will require either CL2 or CL3 parts.
