How safe is it to 'mix' RAM?

laptop memory motherboard

5,958

Solution 1

So as Kevlar said above, It shouldn't be a problem too mix the RAM up but you should still check that the voltage is the same otherwise your laptop will not boot-up.

Your other question regarding the CAS Latency:

Download CPU-Z from here: CPU-Z v1.65

CPU-Z is a free tool. With CPU-Z you can find out CPU-Name, Codename, Technology Core Speed, Multiplier etc. And you can check what your CAS Latency is.

Looks like this: (CPUID Homepage: CPUID)

enter image description here

Solution 2

in most modern machines mixing RAM is generally OK. at least I have never had any issues. But it should be noted that RAM will run at the speed of the lowest module.

So placing 2x8GB in the back slots along with the 2x2GB will not give you the power you might expect. Even though more ram generally means vroom vroom!

4x4GB would be a better option IMO. or Just 2x8GB and remove the 2GB ones completely

5,958

drjrm3

BS - Mathematics MS - Mathematics MS - Computer Science PhD - Computational Science

Updated on September 18, 2022

Comments

drjrm3 almost 2 years

I have a new Qosmio X70 laptop and it has 4 dimms. 2 of the dimms are on the under side of the motherboard and it will be quite difficult to get to. The manufacturer states that it is DDR3L 1600 MHz. The 2 dimms on the backside of the motherboard hold RAM right now (2x2GB) and I want to upgrade.

If I place 2x8GB of 1.35v 204-pin 1600 MHz RAM in the remaining 2 dimms, will that be safe? I wanted to get 4x4GB but I don't want to risk taking out the entire motherboard to do it. I am assuming that it is 204-pin slots because 204-pin is the only 1.35v RAM I can find online.

Also, how can I go about finding the CAS Latency of the installed modules from the OS?

Any help?
- Jason Bristol almost 11 years
  
  I could be wrong, but I don't believe your OS can see the CAS latency of your memory, that is something the BIOS has access to though.
- drjrm3 almost 11 years
  
  I have checked the BIOS as well and couldn't find it. Everything I am finding that is 1.35v (which is not specified as server memory) says 204-pin and has CL 11 ... so I'm wondering if that is the thing to go for.
- gronostaj almost 11 years
  
  Can your motherboard handle 20 GB of RAM? Even if mixing RAM is OK, this may be a problem.
- drjrm3 almost 11 years
  
  It can handle up to 4x8GB.
- Ramhound almost 11 years
  
  You can use any combination you want. Just remember that the fastest memory will be downclocked to the slowest memory. You also want to make sure you supply the expected voltage, if the expected voltage is different, your system is unlikely to boot. The motherboard will indicate what type of memory to use.
drjrm3 almost 11 years

Thanks, one of my questions is mixing memory sizes - so the situation right now would be 2x8GB+2x2GB. Also, not just 'safe', but how efficient is it?
Kevlar almost 11 years

I ammended my answer
drjrm3 almost 11 years

Interesting - so 2x2GB + 2x8GB would actually be worse than just 2x8GB alone? If I need to remove the 2x2 GB then I might as well just go with 4x4 because the whole point of going with 2x8 is so that I don't have to take out the motherboard.
Kevlar almost 11 years

if you really dont want to remove the motherboard then go with the 2x8GB RAM. As long as your motherboard accepts 8GB RAM sticks. but if you are confident in removing it then go with MrSeed's idea with the 4x8GB