RAM CAS latency: compare time as well as cycles
CAS latency is expressed in clock cycles. Comparing its label alone across different data rates can hide the time involved.
RigPrism editorial guide · References reviewed . Not a product test or compatibility guarantee.
Cycles and transfer rate are different units
DDR memory transfers data on both clock edges. A marketed data rate in MT/s is therefore not the same number as its underlying clock in MHz. CAS latency counts clock cycles. To estimate the CAS portion in nanoseconds, use CL × 2000 ÷ data rate in MT/s; this is an idealized timing calculation, not a measured complete-system delay.
Use the calculator with known inputs
RigPrism's RAM latency tool accepts data rate and CL explicitly. Obtain both from the exact kit's rated profile, not from an unrelated product or a screenshot of a different setting. Compare values in the same units and retain the original inputs. If a catalog record has no rated timing, the tool cannot supply that fact and the missing specification should remain unknown.
What the result cannot tell you
The calculation describes one timing term. Other timings, the memory controller, the workload and actual configured settings matter to system behavior. A lower calculated value does not establish a gaming winner or guarantee stability. Check generation, module count and motherboard support first, then use a proper workload test if performance differences are important to your decision. Do not confuse a formula result with a lab observation.
Your check before choosing parts
- Use the exact profile's MT/s and CL.
- Retain units and original input values.
- Treat the result as CAS time, not total system latency.
Reference and scope
Original RigPrism explanation. Manufacturer references establish technical context, not permission to copy product data or images. Verify exact-model documentation before purchase.
Explore another hardware guide