Question Will lower Cas Latency give me better FPS in games?

sapins23

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So currently i have 8gb 2133Mhz DDR4 ram, and im looking to upgrade it to 16GB 2400Mhz DDR4 ram, So there are 2 options for me, one of the rams has 17 CL but the other has 15 CL, i will save about 15 euros if i chose the ram with 17 CL, should i spend more and get the ram with 15 CL, and if so how much more FPS will i get, and will there be a difference between my old 2133 Mhz ram and 2400 Mhz ram.
 

Rhaemond

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So currently i have 8gb 2133Mhz DDR4 ram, and im looking to upgrade it to 16GB 2400Mhz DDR4 ram, So there are 2 options for me, one of the rams has 17 CL but the other has 15 CL, i will save about 15 euros if i chose the ram with 17 CL, should i spend more and get the ram with 15 CL, and if so how much more FPS will i get, and will there be a difference between my old 2133 Mhz ram and 2400 Mhz ram.
To answer your question, relatively, yes your game will be faster if you choose the lower latency RAM. As for the amount of FPS you'll get, that depends still on other factors. Typically, Ryzen systems really benefit from better RAM.
CL timings are just a part in the calculation, and it only differs in a matter of nanoseconds, actually.
Using this link: https://notkyon.moe/ram-latency.htm , a 2400mhz CL15 ram will have a speed of 12.5 nanoseconds while the CL17 one has a speed of 14.1666666 nanoseconds, so around 1.6 nanoseconds of difference between the two latencies.
Are you using a Ryzen CPU? If so, buying a dual channel ram kit (8x2) will get you 2-5 FPS increase. An upgrade from 2133 to 2400 is not really noticeable to speed...
 

sapins23

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To answer your question, relatively, yes your game will be faster if you choose the lower latency RAM. As for the amount of FPS you'll get, that depends still on other factors. Typically, Ryzen systems really benefit from better RAM.
CL timings are just a part in the calculation, and it only differs in a matter of nanoseconds, actually.
Using this link: https://notkyon.moe/ram-latency.htm , a 2400mhz CL15 ram will have a speed of 12.5 nanoseconds while the CL17 one has a speed of 14.1666666 nanoseconds, so around 1.6 nanoseconds of difference between the two latencies.
Are you using a Ryzen CPU? If so, buying a dual channel ram kit (8x2) will get you 2-5 FPS increase. An upgrade from 2133 to 2400 is not really noticeable to speed...
My CPU is intel i5-7500, and so with this CPU is it worth paying the 15 euros more for a 15 CL ram instead of 17 CL or there wont be that much difference?
 

Rhaemond

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My CPU is intel i5-7500, and so with this CPU is it worth paying the 15 euros more for a 15 CL ram instead of 17 CL or there wont be that much difference?
Oh an intel system? Then... Not that much to be fully honest with you. 2-5fps at best. If you have budget for more I'd say get RAM with higher mhz instead but yea, RAM isn't really impactful when it comes to gaming compared to doing video rendering and the like.
 

sapins23

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Oh an intel system? Then... Not that much to be fully honest with you. 2-5fps at best. If you have budget for more I'd say get RAM with higher mhz instead but yea, RAM isn't really impactful when it comes to gaming compared to doing video rendering and the like.
So should i just get the 17CL ram? I cant really get anything higher than 2400Mhz ram because my CPU and MoBo only supports up to 2400mhz.
 

Rhaemond

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So should i just get the 17CL ram? I cant really get anything higher than 2400Mhz ram because my CPU and MoBo only supports up to 2400mhz.
There might be compatibility issues but you can use higher mhz ram and it might run... Consider that, since that's also for future proofing purposes.
Yea CL17 is already good don't sweat on it.
 
Short answer... No benefit.
At the same speed, lower cas is better.
But, that does not translate into a meaningful fps difference if you are using a discrete graphics card.
Here is a study:
http://www.silentpcreview.com/article1478-page1.html

Perhaps of more importance is your ram upgrade plan.
If you are thinking of simply adding ram, reconsider.


Ram is sold in kits for a reason.
A motherboard must manage all the ram using the same specs of voltage, cas and speed.
If you buy higher speed ram, it will operate at the speed of the least capable kit.
The internal workings are designed for the capacity of the kit.
Ram from the same vendor and part number can be made up of differing manufacturing components over time.
Some motherboards, can be very sensitive to this.
This is more difficult when more sticks are involved.

If you do buy more disparate sticks, they should be the same speed, voltage and cas numbers.
Even then your chances of working are less than 100%

What is your plan "B" if the new stick/s do not work?

If you want 16gb, my suggestion is to buy a 2 x 8gb kit that matches your current specs.
Then, try adding in your old 8gb,
If it works, good; you now have extra ram.
If not, sell the old ram or keep it as a spare.