Do lower CAS Latency numbers really make your PC faster?

If you’ve ever tried to upgrade your RAM or build a gaming PC, you’ve probably come across the term CAS Latency. But what is CAS Latency in computer memory, and should you really care?

Stick around, because this post will break down CAS Latency in simple terms, help you understand whether a lower number actually matters, and show you how it compares to RAM speed. You’ll also learn the best CAS Latency for gaming, and how to make smarter buying decisions.

This blog is especially helpful for PC gamers, system builders, tech enthusiasts, and even casual users who want to get the most out of their hardware.

My name is Michel Jongbloed, and after years of researching, benchmarking, and working with performance-based PC hardware, I’ve learned what specs actually matter—and which ones are just marketing fluff.

In this post, we’ll cover:

• What CAS Latency means and how it works.
• Whether a lower CAS Latency truly boosts performance.
• How to compare RAM speed vs CAS Latency.
• Tips on how to lower CAS Latency.
• The good CAS Latency for DDR5 RAM modules.
• And finally, how to pick RAM using a tool like pcmemoryfinder.com, to ensure the best price-to-performance ratio.

What is CAS Latency in computer memory?

CAS Latency (Column Address Strobe Latency) is the delay time between the moment a memory controller tells the RAM to access a specific memory column and the moment the data is available.

Think of it like asking a librarian to fetch a book from a shelf. The time it takes her to locate and hand it to you—that’s your CAS Latency.

So, when your RAM has a CAS Latency of 16, it means it takes 16 clock cycles to complete that operation. Lower numbers mean less waiting time.

Is lower CAS Latency better?

Yes, in most cases, a lower CAS Latency is better—but only when you compare RAM modules with the same clock speed.

CAS Latency alone doesn’t determine the speed. It must be looked at relative to the memory frequency. A RAM stick with CAS 16 at 3200 MHz might perform similarly to CAS 18 at 3600 MHz.

In short: lower latency is good, but only in combination with a strong frequency.

RAM Speed vs CAS Latency: What matters more?

To truly understand performance, you have to consider RAM speed vs CAS Latency together.

Use this simple formula to calculate true latency in nanoseconds:

Latency (ns) = (CAS Latency / RAM Speed in MHz) × 2000

For example:

• DDR4-3200 CL16: (16 / 3200) × 2000 = 10 ns
• DDR4-3600 CL18: (18 / 3600) × 2000 = 10 ns

In this case, they perform nearly identically in terms of real latency.

Best CAS Latency for gaming

If you’re building a gaming rig, timing and frequency both matter, but the difference in CAS Latency only impacts performance slightly in most modern games.

For gaming:

• DDR4 RAM: CL14 to CL16 at 3200–3600 MHz is great.
• DDR5 RAM: A good CAS Latency for DDR5 is CL30 to CL36 at 5200–6000 MHz.

Ultimately, faster frequency matters more for high-FPS gaming, but lower CAS still gives an edge in frame time consistency and loading speeds.

How to lower CAS Latency

Wondering how to lower CAS Latency manually? Here’s how:

1. Enter your BIOS/UEFI settings.
2. Locate the memory timing configuration.
3. Reduce the CAS Latency value in small steps.
4. Stress test your system using tools like MemTest86 or Prime95.

Note 1: This is called memory timing tuning and may require voltage adjustments. Do it only if you’re comfortable with overclocking principles. Note 2: Check this article out on how to adjust RAM settings in you computer BIOS

Choosing RAM with great CAS Latency

Instead of digging through spec sheets, just head over to pcmemoryfinder.com and use their filtering tools.

You can filter by CAS Latency, memory type (DDR4, DDR5), capacity, speed, form factor, and even price per GB. It’s a time-saving way to find high-performance RAM that fits your needs—and your budget.

Final Thoughts: Should you care about CAS Latency?

Yes, but don’t obsess over it. Lower CAS Latency can improve real-world responsiveness and multitasking, especially if you’re tuning a high-end build. But if you’re gaming or using general applications, frequency and capacity often have a greater impact.

The sweet spot is balanced RAM: good speed, reasonable CAS Latency, and a decent price.

Call To Action

Ready to upgrade your RAM with confidence? Visit pcmemoryfinder.com to find the best memory modules based on real-world performance and value. Stop guessing, start building smarter.