RAM Latency Calculator (True ns)

Data reviewed July 19, 2026 · Methodology

Compare memory kits fairly. CL alone lies — true latency in nanoseconds is what counts.

How to compare RAM latency

DDR speed and CAS latency describe different parts of a memory access. Converting them to first-word latency in nanoseconds makes unlike kits easier to compare, but it does not capture every timing or platform effect.

Step by step

1. Enter the advertised data rate, such as DDR5-6000, and the primary CAS latency value.
2. Compare the calculated nanoseconds between kits that are compatible with the same platform.
3. Check capacity, module count, voltage and motherboard memory support before choosing the lower number.
4. Install a two-module kit in the board’s recommended paired slots and enable the memory profile.

How to read the result

First-word latency equals CAS latency multiplied by 2000 and divided by the DDR data rate. Lower is better for that one timing, while bandwidth rises with data rate. Real application performance also depends on secondary timings and the memory controller.

Common mistakes to avoid

• Comparing CL numbers alone; CL30 at one speed is not the same delay as CL30 at another speed.
• Buying four high-speed modules when the platform is more stable with two.
• Assuming XMP or EXPO speed is automatic instead of an overclock profile that must be enabled.
• Ignoring capacity needs to gain a tiny latency advantage and then forcing applications to page to storage.

Verify before you buy or change settings

Check the motherboard QVL and memory vendor configurator for the exact part number, CPU generation and module count. After installation, confirm the effective data rate and run a memory stability test. A kit can boot while still producing intermittent errors under load.

Calculator logic and this guide were reviewed July 19, 2026. See the methodology and limitations.

Frequently asked questions

Is a higher CAS latency (CL) always worse?

No; CL is only half the story. True latency in nanoseconds is CL divided by the data rate, so a DDR5-6000 CL30 kit and a DDR4-3200 CL16 kit both land near 10ns despite very different CL numbers.

What RAM latency is good for gaming in 2026?

On DDR5, aim for roughly 10ns or lower; DDR5-6000 CL30 is the sweet spot for AMD AM5 because it also syncs 1:1 with the memory controller.

Does RAM latency or speed matter more for gaming?

They work together; what matters is the true latency in nanoseconds and the bandwidth from the data rate. A balanced kit like DDR5-6000 CL30 optimises both.