Possible values of an option:
Depend on memory type, there can be a variant [Auto] or [By SPD]
The option description:
Establishes a delay in steps between delivery of signal CAS and the data reading beginning (parametre tCL in the access diagramme). For the majority of qualitative modules of memory of type SDRAM of standard PC66, PC100 and PC133 it is possible to establish value . If stable work in this case is not provided, lower value of an option to . For modern modules of memory DDR SDRAM this value is equal , [2.5] or , modules DDR2 SDRAM and DDR3 SDRAM is characterised on the average by some great value — from  to  and from  to  accordingly. If there is a variant [Auto] or [By SPD], value CAS Latency undertakes from microcircuit SPD. Installation большей delays raises stability of work of the computer, but negatively affects speed.
Delays at the reference to memory in most cases directly depend on frequency of the tyre of memory. The above this frequency, the is more than delay. For example, typical module PC2100 is characterised CAS Latency, equal 2, for module PC2700 value 2.5 is more likely characteristic, well and the majority of usual modules PC3200 have delay CAS Latency equal 3. The similar tendency is present and at modules of memory DDR2 SDRAM, DDR3 SDRAM. This remark is fair not only for CAS Latency, but also for all other delays in the diagramme (formula) of access.
Other options identical to destination: