What Is CAS Latency for DDR Memory?

An assortment of RAM sticks. There's got to be one with low CAS latency in there.

All double data rate (DDR) memory modules are set apart by two primary factors: speed, or frequency; and timing, or Column Access Strobe (CAS) latency.

Significance

CAS latency refers to the amount of time it takes for data to appear on the pins of the memory module. The lower the CAS latency, the lower the number of clock cycles it takes to read and write to the memory. Another important factor of CAS latency is row access strobe-to-CAS delay, which affects the speed of the memory's overall timing.

Benefits

DDR RAM with lower CAS latency can be over-clocked more effectively in most cases. It may increase the performance of many applications that access RAM frequently, such as graphically intense video games and large drafting and design programs.

Considerations

When building a gaming PC or a high-performance desktop computer, DDR memory timing may be an important factor due to its advanced over-clocking capabilities. However, CAS latency is a specification that will not matter to most computer users. Unless you plan on over-clocking, you won't need to worry about CAS latency.

References

• Memory Suppliers: CAS Latency