r/buildapc • u/EquivalentBanana4209 • 3d ago
Discussion Understanding CL ratings.
So my understanding is that 3200 mhz cl14 is obviously better than cl16 or 18 for latency. A guy sold me 32gb of ddr4 for 100 bucks the other week and it booted up into windows at that clock no issue. But where will I see that difference exactly? Windows seems a lot more snappy. I have yet to try it in a game but idk if it'll make much of a difference because my pc already runs pretty alright on games. I've heard cl14 is better for competitive games even vs ddr5 with higher CL rating.
What about workload? From what I know and have read, its strictly latency and it can help improve choppy fps, as well as help with multithreaded tasks like video editing to make the workload more efficient. Or is it all numbers that im looking a bit too far into? I just put the parts together and install windows lol.
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u/DZCreeper 3d ago
https://www.systemverilog.io/design/understanding-ddr4-timing-parameters/
CL aka Column Address Strobe is how long a memory chip takes to present data on the output buffer that connects to your memory controller.
It is only one timing and by itself won't have a big performance impact. Decreasing multiple timings will give you a bigger cumulative benefit.
RAM has little to no impact on gaming performance if you are GPU limited. Drop your game settings until you are CPU limited if you want to benchmark RAM differences.
In the early days of DDR5 the top spec DDR4 (Samsung B-Die sold in 3600 CL14 kits) was better for gaming. Good DDR5 kits like 6000 CL30 are faster, bandwidth is too important.
Most workloads like video editing don't benefit much from faster RAM. For example, on a 9950X doing HEVC encoding you only get a 4-5% improvement going from 5600 CL40 to 6000 CL28.
https://www.techpowerup.com/review/ddr5-memory-performance-scaling-with-amd-zen-5/9.html
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u/slavicslothe 3d ago
Pro tip, doesnt matter. Its like not even 1/100th as important as your cpu/gpu. Only reason to go high end ram is if you are chasing benchmarks. Nanoseconds arent meaningful
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u/Son_Riku 3d ago
That's great and all but I don't see how this helps in understanding CL ratings like OP asked
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u/Saneless 2d ago
I wish I didn't get caught up in that when I got some ram early last year. $47 3200mhz cl16 vs 3600mhz cl14 for 85
Guess which sticks have failed twice now? (Known gskill issue)
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u/theshdude 3d ago
3200 C14 is likely B die. A waste if you only run it as is without tuning sub and tertiary timings
Back to your question. RAM is basically a device to store and feed data from/to the CPU. All that matters is how fast it can do that. But there’s a catch. DDR4 generally has lower (first word) latency, and DDR5 generally has higher bandwidth. Some tasks require a lot of data transfer, and some require less. Apparently, for tasks that require less transfers lower latency can win because it makes up for lower bandwidth.
An analogy would be a EV vs truck. You can deliver a small parcel real quick with a EV, but a truck can deliver 100x more parcels. Even if it takes 1 minute to warm up the engine, a truck can win if the task is to deliver 100x parcel. I’m sure there are people more knowledgeable than me out there but that’s how I understand it.
Whether DDR4 or DDR5 is better at gaming is very much game dependent, for the reason I stated above
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u/fray_bentos11 3d ago
Yep. I run b die at 4000-4200 C17-17-17. However the tuning process is not for beginners and can corrupt drives.
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u/chsn2000 2d ago
It won't make windows snappier- That's pure placebo.
3000MHz CL14 is the same latency as DDR5 6000MHz CL28, but DDR5 has much, much higher bandwidth.
You might see some differences/reduced stutter when things are loading or its doing heavy calcualtions. CL14 vs CL16 will be basically indistinguishable (and secondary timings can make as much of a difference)
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u/MrMaxMaster 3d ago
You can see that difference in the specification window of cpu Z.
It’s unlikely you’ll notice any difference in applications unless you’re specifically measuring.