How to Check RAM CAS Latency? – Learn Here

Last Updated on January 16, 2021

CAS latency, along with clock speed and capacity, plays an essential role in the overall performance of RAM in a computer.

It’s also a crucial factor to consider while replacing or upgrading RAM modules. In this article, we explore the ways as to how to check RAM CAS latency.

TL;DR. The CAS Latency can be determined directly using free applications such as CPU-Z and Piriform Speccy. You can also find the part number of a memory module using Command Prompt in Windows 10 and use it to check the CAS latency on the internet. Moreover, you can examine the printed labels or stickers on the RAM modules to check the CAS latency directly or indirectly.

Again. while many people think that only size and speed matter for RAM, it’s also the timings including CAS latency that needs to be considered.

How to Check RAM CAS Latency?

As CAS latency is a significant parameter of RAM and measured in clock cycles, we cover here different ways that would help you to determine this for a Windows-based PC.

Here’s how:

1. Using CPU-Z Software

How to Check RAM CAS Latency

CPU-Z is a free and widely used software that’s useful in determining lots of information about your device including the RAM CAS latency. Follow the steps stated below for this purpose:

  1. Download and install the CPU-Z application from the CPUID official website.
  2. Run the application and head over to the Memory tab.
  3. Read the value of CAS Latency (CL) mentioned in the Timings box. It should be mentioned in clocks which means clock cycles. For instance, it may be specified as 11.0 clocks which means your system is running on RAM with this CAS latency.
  4. Come to the SPD (Serial Presence Detect) tab. Here you should see the speed and timing information for the RAM modules installed on your computer. Use the drop-down list in the Memory Slot Selection box to switch between the modules.
  5. You can find maximum CAS Latency in the JEDEC #7 column of the Timings Table box. Note that this applies to memory that has not been overclocked for increased speeds.
  6. Alternatively, you can search for the CAS latency of a RAM module in a browser by typing its part number given in the SPD tab. Try to visit the official page of the manufacturer or an authentic shopping website from the search results to find accurate information.

2. Using Piriform Speccy Software

There’s another useful utility called Piriform Speccy that provides you information regarding CAS latency of the memory modules. Below are the steps to follow:

  1. Download the free version of the Piriform Speccy software from the official website.
  2. Run the application.
  3. Navigate to the RAM section.
  4. Here you can find the CAS latency and it will be given in clocks.
  5. Expand the SPD subsection.
  6. Pay attention to the JEDEC #7 part of the Timing Table of each memory module in the slots. Here maximum CAS latency of a specific memory module will be given.
  7. You can repeat the above step to find the maximum CAS latency of all the memory modules installed in your system.

3. Using Command Prompt in Windows

command prompt ram

Here’s another way to find out the RAM CAS latency if you don’t want to make use of the above-mentioned software. It can be done by determining the part number of each memory module via Command Prompt in Windows 10 and then searching for it on the internet. Follow the steps below:

  1. In the Windows search bar, type Command Prompt.
  2. Right-click the top result. Choose Run as administrator option.
  3. Copy and paste the following command:

wmic memorychip get devicelocator, partnumber

  1. Press Enter.
  2. You will be provided with the part number of each memory module under the “PartNumber” column.
  3. Copy a part number and paste it in Google. In the search results, visit the manufacturer’s page to find the CAS latency of a specific module.

4. Physically Examine RAM Modules

ram module label
Source: Samsung

You can open the casing and notice the pasted label or sticker of a RAM module.

On closely examining it you may find information like manufacturer, part number, or serial number. Note that this may be difficult to do in the case of an AIO PC or a laptop.

Simply you need to record the information and search for it in a search engine. The results would take you to different pages where you can find the CAS latency of the RAM whose serial number matches that printed on the sticker.

We recommend visiting the manufacturer’s official website to check the CAS latency.

There’s another way to check RAM CAS latency by examining the sequence of numbers (better known as RAM timings) if it’s printed on the sticker of a RAM module.

For example, if the sequence is printed as CL9-9-9-24 or CL16-18-18-36, the number after the CL is used to denote the RAM CAS latency (also called CL). In this case, 9 and 16 is the CAS latency respectively, measured in clock cycles.

Why CAS Latency Matters for RAM?

CAS latency, also called Column Access Strobe, is the time taken for the RAM module to respond to a data request. In other words, it’s the delay to produce a dataset by column of RAM.

When two RAM options having an identical size and clock speed are compared, the one with a lower CAS latency should provide better performance. This means that the lower the CAS latency, the faster is the RAM and as a result more costly in price.

Keep in mind that even though a RAM module can be considered quicker if it has a lower CAS latency, a higher clock speed is still a more important factor to be considered when upgrading RAM.

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Doubtlessly, RAM is an important component of a computer. By knowing how to check RAM CAS latency along with other factors such as size and clock speed, you will be in a better position to be aware of the functioning of your existing RAM modules.

Demanding users like streamers or gamers or those building a PC especially need to keep this in mind.

Also choosing RAM for an upgrade can have a direct impact on your computing experience. Therefore, we recommend selecting RAM modules with the same clock speed and CAS latency for optimized performance.


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