a dimm memory ad displays 5-5-5-15. what is the cas latency value of this dimm?

The CAS latency value of a DIMM labeled 5-5-5-15 is 5 clock cycles. In standard memory timing notation, the first number in the sequence (here, the first “5”) represents the CAS latency (often written as CL). An example explanation of this same pattern notes that for timings like 5-5-5-15, “the first value is the CAS latency, which would mean that in this case, this module is CL5.”