What does the figure order 2-3-3-7-1 exactly mean?
The 1st figure ALWAYS refers to the CAS Latency (CL).
The 2nd figure refers to RAS to CAS
The 3rd figure refers to RAS Precharge
The 4th figure refers to the active RAS time
The 5th figure refers to the command rate
These indications (except of CL) can of course differ depending on the manufacturer, but generally this composition of figures is used by default.
CAS Latency (CL): The CAS Latency corresponds to the delay between the addressing and the supply of the data stored at this address. The value behind the CL indicates the cycles. Possible are 2.0, 2.5 and 3.0. The lower the latency value is the better it is but also the processor will be more expensive.
RAS to CAS: This corresponds to the cycle value (2 or 3) which is between a value on the CAS (column address) and a value on the RAS (row address). The figures on the chip set which are of the type 3-2-2 refer to the CAS, RAS-to-CAS and RAS. If a chip set with a higher transfer rate is being used this means that you break the CAS/RAS limit.
RAS Precharge: The RAS Precharge refers to the cycle value (2 or 3) which is saved in the RAS before it is deleted.
RAS Active Time (tRAS): This is the cycle time during which the value remains activated on the RAS. In the BIOS manual it is indicated that it will be activated 7 or 8. But in practice it remains activated only 5 or 6. This means that the lower the cycle time is the more rapid is the run time.
Of course there is still more choice on the market but those mentioned here are the most known as they had been used quite often. The CL2.0 is only interesting for the user if he wants to use it for overclocking. The CL2.5 or CL3.0 refers to the perfect latencies for the standard user. There are hardly any differences but for the CL2.5 the compatibility is generally better. If you still do not know which latency is the right one for you we recommend you to buy the CL2.5 as it is more compatible than the other ones.