Cycle latency refers to the time it takes for a system or component to complete one full cycle of operation.
Cycle latency refers to the time it takes for a system or component to complete one full cycle of operation.
I don't get it. What are you referring to with CL16, CL19, CL21 and other?
CAS latency measures the time between issuing a read request and receiving the data. It reflects the number of clock cycles needed before the first byte becomes accessible. A CL16 device requires 16 cycles to deliver readable data. Lower CAS values indicate faster memory performance, provided the clock speed remains constant.
CL indicates how many cycles are needed to execute a particular memory task. You often encounter terms like "primary timings," such as 16-18-18-38, but there are many more settings beyond these. It can become quite complex, yet those primary timings usually play a key role in performance, which is why they matter so much. Another factor is the RAM's operating speed. For DDR memory, the listed speed is double the clock frequency. DDR4-3200 operates at 1600MHz, even though it processes data twice per clock cycle, resulting in roughly 3200 transfers per second—measured as MT/s. That figure isn't misleading; it reflects the actual performance. If you're using DDR4-3200 CL16, it means 16 clock cycles are needed for each operation. This timing is crucial because it represents the "CAS latency"—the delay from sending a command to receiving a response. The CPU requests data, and it takes 16 cycles before the RAM can start supplying it. Since DDR4-3200 runs at 1600MHz, there are 1.6 billion cycles per second. Dividing that gives the time needed for 16 cycles, which comes out to about 10 nanoseconds. This means the RAM must respond in roughly 10 nanoseconds for each request. Each RAM type's speed and timing combination define its latency, which ultimately shapes how fast it works. DDR4-3600 CL16 is not only quicker in data throughput but also completes more cycles per second, cutting its response time to 8.89 nanoseconds. Conversely, DDR4-2400 CL16 is slower at 1200MHz, needing 13.33 nanoseconds, while DDR4-3200 CL14 would still run at 1600MHz but take 8.75 nanoseconds for the same task. If you swapped to DDR4-3600 CL18, its latency would match the first example at 10 nanoseconds.
Explanations are clear from previous discussions. Focus on achieving a lower CL value, aiming for RAM with a CL no greater than 1/2000 of the rated clock speed for DDR4. For a 3200MHz processor, this means a maximum CL16. A kit showing CL18 or higher for 3200MHz indicates poor quality and should be avoided.