Free RAM latency calculator to determine true memory latency in nanoseconds from DDR4/DDR5 frequency and CAS timings. Compare memory kits and optimize your PC build.
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Memory speed isn't just about MHz - latency matters too. Our calculator converts CAS latency timings to real-world nanoseconds, helping you compare DDR4 and DDR5 memory kits to find the best balance of speed and responsiveness.
RAM latency is the delay between requesting data and receiving it. While higher frequency (MHz) means more bandwidth, CAS Latency (CL) determines how many clock cycles until data arrives. True latency in nanoseconds combines both factors.
Latency Formula
Latency (ns) = (CAS Latency ร 2000) รท Frequency (MHz)Lower latency reduces frame time variance and improves 1% lows, especially in CPU-bound games.
Applications that frequently access memory benefit from faster response times.
Compare DDR4 vs DDR5 kits fairly - DDR5 has higher CL numbers but also higher frequencies.
10ns latency - great budget choice for gaming and general use.
7.78ns latency - excellent for Ryzen systems, top-tier DDR4.
10ns latency - sweet spot for DDR5 with high bandwidth.
10ns latency - fast DDR5 matching DDR4-3200 latency.
Both matter. For gaming, aim for sub-10ns true latency. For productivity requiring bandwidth (video editing, compression), higher frequency helps even with slightly higher latency.
DDR5 runs at much higher frequencies, so even with higher CL numbers (30-40), the true latency in nanoseconds is similar to DDR4. DDR5-6000 CL30 equals DDR4-3200 CL16.
Under 10ns is excellent. 8-9ns is very good. Most DDR4-3200+ and DDR5-5600+ kits achieve this. Below 8ns provides diminishing returns.
Yes! XMP (Intel) and EXPO (AMD) profiles set both frequency and timings. Always enable these in BIOS to get advertised speeds rather than JEDEC defaults.