Memes Jul 11, 2020 @ 7:56am
Found out my laptop Ram CAS Latency is mixed. Is that bad?
Laptop came with 8GB and I wanted to have 16 GB and I didn't want to spend extra money on buying 2 sticks so I just got one instead and used the generic one as well. I found the one that is exactly the same and when installed, laptop booted up and everything was fine. So a year later I look at my ram specs for no reason and found out that my Corsair ram and the other ram has different CAS Latency. Everyone I talked to and the responses on this fourm said it was fine to mix match ram if they match the speeds and everything but didnt say anything about CAS Latency. It won't like fry my laptop would it?

Pictures below

https://steamcommunity.com/sharedfiles/filedetails/?id=2162499854

https://steamcommunity.com/sharedfiles/filedetails/?id=2162499216
Originally posted by r.linder:
If it works, it's fine. OEMs do that all of the time in both laptops and desktops.
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Showing 1-9 of 9 comments
Bad 💀 Motha Jul 11, 2020 @ 8:02am 
If it works without causing all sorts of random crashes then it's not a problem. The bios will just use the higher/slower Cas timings for all installed ram.

Pictures just show what's possible for that ram based on its various profiles. Click the other memory tab to show you how it's actually running.
Last edited by Bad 💀 Motha; Jul 11, 2020 @ 8:04am
_I_ Jul 11, 2020 @ 8:20am 
most cheap laptops they dump in whatever ram is the cheapest and will do the job

ddr speed = freq * 2
the 2333 (1663 * 2) cl 16 is the best xmp/spd profile (2333 / 16 = 145) its pretty bad even for oem/generic

the corsair dimm is slightly better
2400 / 16 = 150, but still at the generic performance level

its hard to find high performance laptop dimms with larger size and still 1.2v

you can try overclocking the generic dimm to 2400 (1200mhz), its not a huge jump
test with ibt or prime95 blend for a few minutes, if it does not crash call it stable enough

but just having more ram and in dual ch will help alot more vs the single 8g dimm
Last edited by _I_; Jul 11, 2020 @ 8:21am
KeplersConjecture Jul 11, 2020 @ 8:30am 
Its not ideal, but not a huge problem, the laptop will just use the slower common CAS timings.

You can get a matching Corsair 8g DDR4 2400 stick for about 32usd. Up to you if that is worth it or not.
Memes Jul 11, 2020 @ 8:55am 
So pretty much nothing would go wrong the laptop would just match the speed to both rams right?
_I_ Jul 11, 2020 @ 8:59am 
when mixing ram its best to use common speed and timings with both kits
they can run with lower speed and higher timings
Memes Jul 11, 2020 @ 9:12am 
Yeah ik but didnt know about the cas latency had to be the same as well. I'll just buy the 2 of the same ram sticks in the future
The author of this thread has indicated that this post answers the original topic.
r.linder Jul 11, 2020 @ 9:37am 
If it works, it's fine. OEMs do that all of the time in both laptops and desktops.
Last edited by r.linder; Jul 11, 2020 @ 9:44am
vadim Jul 11, 2020 @ 9:41am 
Originally posted by _I_:
when mixing ram its best to use common speed and timings with both kits
they can run with lower speed and higher timings
This ^. Timings difference never makes any problem for me.
Bad 💀 Motha Jul 11, 2020 @ 10:02am 
As long as both are the same speed, like 2133, if that's what the original one was, then you should be fine.

Then both should have a range of CAS timings similar enough that the BIOS should be able to determine what can work for both via SPD "Auto".

In the end it should settle for the same speed (2133, 2400, 2666 Mhz), CAS timings (i.e. 16-16-16-24-32-2T) and Voltage, which for under 2800mhz DDR4 typically should be 1.2V

What I also never like to mix are the chip makers on the actual RAM. Such as Hynix, Micron, Samsung. As you are just more likely to have stability issues by mixing them.
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Date Posted: Jul 11, 2020 @ 7:56am
Posts: 9