CAS or Column Access Strobe (sometimes also called Column
Access Select) Latency refers to the timing delay before the initial burst of
data is processed by the computerís RAM.
It is expressed in clock cycles and modules are often rated at CL2 for 2
cycles, CL3 for 3 cycles, and so on.
Modules with CL2 rating fetch data one cycle faster
than CL3. There is, however, no difference after the initial part of data is processed.
The rest of the data is processed at equal rate. Majority of systems will accept either
latency rating, however, there are still some that may allow only the rating specified
by the motherboardís manufacturer.