To check the CAS latency currently reported for your RAM in Windows, open CPU-Z, select the Memory tab, and read CAS# Latency (CL). To see the timing data stored on an individual RAM module, use the SPD tab and select its slot. Those readings answer different questions: Memory shows the active timing, while SPD shows module information and supported profiles.
Check the active CAS latency with CPU-Z
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Download or launch CPU-Z from CPUID’s official CPU-Z page. CPUID describes the utility as reporting memory type, size, timings, real-time frequency, and module specifications from SPD.
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Open the Memory tab and find CAS# Latency (CL). This is the timing the system is currently reporting as active. Note the memory frequency and other displayed timings too if you are comparing configurations; CAS latency alone does not describe the whole memory setup.
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For an example of how the field appears, Intel’s NUC6i7KYK guide shows CPU-Z reporting CAS# Latency (CL): 17.0 clocks, alongside other timing fields. That is an illustration for that system, not a recommended setting or a benchmark result. See Intel’s NUC6i7KYK guide.
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Check a module’s stored timings on the SPD tab
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In CPU-Z, open the SPD tab.
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Select a populated memory slot from the slot selector.
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Review the module identification and its timing table or profiles. These describe data stored for the module and available profiles; they do not necessarily show what the system is using right now.
CPU-Z’s SPD information can include extended profiles such as EPP or XMP, which helps explain why a module’s stored specifications or profiles may differ from the active values shown on the Memory tab. CPUID explains CPU-Z’s memory and SPD reporting.
Find CAS latency in BIOS or UEFI
Some firmware setup screens display CAS latency as CAS Latency or tCL. The exact menu location and available details vary by manufacturer and model, so consult the manual for your computer or motherboard rather than assuming a universal path.
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For a model-specific example, Intel’s NUC8i7HxK Overclocking Assistant shows a BIOS/UEFI memory settings screen with CAS Latency (tCL) 18. This is an example from that system, not a general specification. See Intel’s NUC8i7HxK guide.
Independent reader supportYour contribution helps us test, update, and keep practical guides available for everyone.Why CPU-Z’s Memory and SPD readings can differ
The tabs report different kinds of information. The Memory tab shows the timing currently reported as active; SPD shows module data and supported profiles. A supported profile is not proof that the system is using it. Compare active values with active values, or stored profiles with stored profiles—not one category against the other.
How to interpret a CL number
CAS latency is shown in clock cycles in the cited timing displays. A lower CL number by itself does not establish that one memory configuration is faster overall. For a meaningful comparison, check that the values describe the same kind of setting, then account for the memory generation, operating data rate or frequency, and the rest of the timing set. The CL figure alone is not enough to rank configurations or convert cycle counts into real-time latency.
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