RAM Latency Calculator

What is Real RAM Latency?

The CAS latency number (e.g. CL16) is measured in clock cycles, not time. To find the actual time delay your CPU waits for memory access, you need to convert it to nanoseconds using the memory clock speed.

The formula is: Real Latency (ns) = (CL × 2000) ÷ Speed (MHz)

This means a 3200 MHz CL16 kit and a 3600 MHz CL18 kit both result in exactly 10 ns latency — the faster speed compensates for the higher CL number.

Latency Tiers for Gaming

≤ 9.5 ns — Excellent: Ideal for competitive gaming. Reduces frame time variance and input lag.
9.5–11 ns — Great: Excellent performance for all gaming scenarios.
11–13 ns — Good: Solid for casual gaming. Marginal impact in most titles.
> 13 ns — Poor: May cause stutters or frame time inconsistencies in fast-paced games.

DDR4 vs DDR5 Latency

DDR5 kits often have much higher CL numbers (e.g. CL40) than DDR4, but their higher MHz speeds keep real latency competitive. A DDR5-6000 CL30 kit delivers ~10 ns — the same as DDR4-3200 CL16. Always use this calculator to compare kits by their real latency, not just the CL number.