Can I mix CAS levels in a 4 Dimm slot laptop?

[MagicBlueMan]

I just got a P75-A7200 Toshiba laptop.

Url is here if you're interested: http://us.toshiba.com/computers/laptops/satellite/P70/P75-A7200/

It has four dimm slots. 2 are empty.

Using the program RAMMon it appears I have two 4 GB dimms (8 gb total) in the two other slots. They are DDR3-1600 with 11-11-11-28 timings.

I'm going to buy two 8GB Dimms for the empty slots. Can I get some with different timings?

I was thinking of getting these http://www.newegg.com/Product/Produc...82E16820231582 which has a CAS latency of 10. Will that be a problem? Should I match the 11-11-11-28 instead?

I might some day replace the two 4GB modules as well, so it would be nice to have better timings on these new modules.

Two more questions:

* My understanding is correct that a lower CAS is better, right?

* Can one actually notice a difference going from CAS 11 to CAS 9? Or is it purely academic?

Thanks

 

[MagicBlueMan]

Since I haven't gotten an answer, I might as well ask:

Is there a better forum or site to ask this question on? Maybe a laptop site?

Thanks!

 

[razel]

Using CAS latency of 10 will not be a problem. Laptops will choose the slowest timing between all the RAM sticks.
You don't have to match the 11 timings.
Lower CAS is better.
You will not notice the difference, but you can bench it and out of all the memory upgrade reasons, going to a lower latency is generally best. Going with a higher speed however is better for integrated graphics especially if the laptop is from the past 2-3 years. Yes, notebookreview forums in my opinion is a far better resource for notebook related questions. There are several threads there that deal with CPU/GPU/RAM overclocking and tweaking. Amazing!

However here's some advice with forums in general. We now live in the information age and info is money. You are getting it here for free. Gurus work for a living during weekday so get used to being patient. If you want answers right away, ask a PC guru friend or pay someone. Have fun!

 

[MagicBlueMan]

razel...

Thank you so much!

And my question about other forums wasn't meant as a complaint. It was just because I thought someone might read this question, not know the answer, but know of another good resource.

Thanks again!

 

[cytg111]

Lots of other good resources outthere, easy to find, you'll nail em with google .

In theory and practise, yes you can mix dimms. You could problary do it and never have an issue with it. Personally I wouldnt do it. Memory is a slippery thing and the next time I am to have memory issues(let it never happen again) I would have to factor that into the equation too. Memory is like this : Install, run test, all good? Never touch again.
To me anyway.

 

[Gillbot]

Using CAS latency of 10 will not be a problem. Laptops will choose the slowest timing between all the RAM sticks.
You don't have to match the 11 timings.
Lower CAS is better.
You will notice the difference, but you can bench it and out of all the memory upgrade reasons, going to a lower latency is generally best. Going with a higher speed however is better for integrated graphics especially if the laptop is from the past 2-3 years. Yes, notebookreview forums in my opinion is a far better resource for notebook related questions. There are several threads there that deal with CPU/GPU/RAM overclocking and tweaking. Amazing!

However here's some advice with forums in general. We now live in the information age and info is money. You are getting it here for free. Gurus work for a living during weekday so get used to being patient. If you want answers right away, ask a PC guru friend or pay someone. Have fun!

Typically they will yes, but i've had a few that would crash or error when mixing due to the speeds not detecting properly. When I switched to matched sets, the crashing or errors went away.

 

[JBT]

While everything should be fine to mix the two, we can never be certain. Even RAM with the same settings may not work correctly. I'd like to think we are past those days but I haven't had a reason to mix RAM in years.

Also the difference between CAS 9 and 11 in a laptop is not going to be noticeable at all. Heck even in high performance rigs who are just going to the best in benchmarks are hard pressed to see differences related to RAM timings.