Question Upgrading ram - Understanding mhz/CL numbers

Kayeye

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Mar 6, 2011
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I have an Acer laptop (A515-43-R5RE) with 8gb and I'm looking to upgrade it. I'm confused on the numbers being listed and what is better. I think the max is 32gb on this machine and being that 16gb sticks are fairly cheap, I'd like to get 2 of them but I have no idea on the numbers being listed. Take these for example:

2400 (PC4-19200) CL16 Unbuffered Non-ECC 1.2V
3200 PC4-25600 CL22 Unbuffered Non-ECC 1.2V
PC4-21300 DDR4 2666 CL19-19-19-43 1.20V Dual Channel


They seem to be going for close to the same price.
 

keith12

Illustrious
Hey there,

So firstly you should be looking at SO-DIMMs. What CPU is in your laptop? Ryzen 5 3500u? So it's IMC supports 2400mhz SO-DIMMs. Anything with faster speeds may not function as expected.

Both speeds (e.g 2400mhz) and CL rating (CL19 or CL20 or whatever) are important. In your case choose 2400mhz with as low CL as you can get. This gives you the most theoretical bandwidth on the ram. Ideally you want a 2 x 8gb config or 2 x 16. Is your existing ram two sticks or one stick? Also, is it soldered, or can it be removed? If it's soldered, you may be only able to add one more stick, which must match your existing ram pretty closely.
 
Reactions: Kayeye
I have an Acer laptop (A515-43-R5RE) with 8gb and I'm looking to upgrade it. I'm confused on the numbers being listed and what is better. I think the max is 32gb on this machine and being that 16gb sticks are fairly cheap, I'd like to get 2 of them but I have no idea on the numbers being listed. Take these for example:

2400 (PC4-19200) CL16 Unbuffered Non-ECC 1.2V
3200 PC4-25600 CL22 Unbuffered Non-ECC 1.2V
PC4-21300 DDR4 2666 CL19-19-19-43 1.20V Dual Channel


They seem to be going for close to the same price.
Look here.
https://www.crucial.com/compatible-upgrade-for/acer/aspire-a515-43-r5re

Find the 2x16GB@2600 KIT.
 
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Kayeye

Distinguished
Mar 6, 2011
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Hey there,

So firstly you should be looking at SO-DIMMs. What CPU is in your laptop? Ryzen 5 3500u? So it's IMC supports 2400mhz SO-DIMMs. Anything with faster speeds may not function as expected.

Both speeds (e.g 2400mhz) and CL rating (CL19 or CL20 or whatever) are important. In your case choose 2400mhz with as low CL as you can get. This gives you the most theoretical bandwidth on the ram. Ideally you want a 2 x 8gb config or 2 x 16. Is your existing ram two sticks or one stick? Also, is it soldered, or can it be removed? If it's soldered, you may be only able to add one more stick, which must match your existing ram pretty closely.
Yes, it's the 3500u and it has one 8gb stick that's removable. Bob mentions that I should look into the 2600 kit. Would there be any issues going with that speed instead of the 2400?
 

keith12

Illustrious
What speed does your current ram run at? Run CPU-z and go to the mem/spd tabs and take note of the model. Whilst faster ram might work, it's not a given. You might be better off just adding another single stick of ram, to keep costs low. Laptops are much more forgiving in terms of mixing ram modules than desktops (where a matched kit is best option).
 
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geofelt

Titan
The numbers 2400 and 3200 are the speeds at which the ram can transfer data.
Higher is faster.
The cl numbers 16 and 19 are the latency numbers, They indicate how many cycles it takes to get the transfer started. Lower is better.
The info you listed is for desktop ram; you need laptop ram.

A motherboard must manage all ram at the same speeds, cas and voltage.
You must buy a single 2 x 16gb kit to insure that the ram must be matched.

Ryzen may be sensitive to ram.
Best to access a ram site like kingston or corsair and find their ram upgrade app.
Enter your laptop info and you should get a list of compatible upgrades.
Buy an exact part number listed if you can.
If you must, buy a kit with the same specs.
 
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Kayeye

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Mar 6, 2011
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I ended up getting two of the 8gb 2666mhz sticks from the link above. I got it installed but under task manager, it shows 2200mhz I think (I’m not home atm). According to the crucial site, it should be compatible. Is there another way to check if the ram is working right?
 
I ended up getting two of the 8gb 2666mhz sticks from the link above. I got it installed but under task manager, it shows 2200mhz I think (I’m not home atm). According to the crucial site, it should be compatible. Is there another way to check if the ram is working right?
When you say two 8GB sticks was that 2 separate sticks or a kit of 2?
 

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