RAM Upgrade for Dell Studio 1749 - help me get it right please

sp2011

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Hi all,

I have Dell Studio 1749 i5 notebook and it came with 4gb of RAM - I am running Win 7-64bit and do a lot of work in Photoshop CS5 & After Effects. I would like to increase the RAM to 8Gb.

I am a little confused regarding the CAS latency though!

The manual states the following RAM should be installed :

Memory module connector
two user-accessible SODIMM connectors
Memory module capacities
1 GB, 2 GB, 3 GB,
4 GB, 5 GB, 6 GB,
and 8 GB
Memory type
1066 MHz SODIMM DDR3 (Studio 1745/1747/1749)
1333 MHz SODIMM DDR3 (Studio 1747)
Minimum memory configuration
1 GB
Maximum memory configuration
8 GB



When I run CPU-Z I get the following info re my currently installed RAM :

cpuz1.gif


cpuz2.gif


cpuz2.gif



(which leaves me confused about the speed the current ram is running at even though it seems to be 1333 memory - although the Hyundai datasheet for this ram states it is CAS 9 - the H9 revision of the module)

Now, when looking for a replacement set of SODIMM's (2 x 4Gb) I came across this one :

Corsair RAM Chips

(chosen because the supplier is close to me).

I was about to purchase but was worried because the CAS latency is stated as 9 so I am awaiting advice before I purchase - Can anyone help please or recommend a more suitable upgrade?

Many thanks in advance,
Si.
 

sp2011

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Hi tokencode - thanks for the post - much appreciated. I had, actually, looked at the ram from Crucial (even ran there scanner) and it came to the same RAM you have pointed out.

However, I am STILL confused - even the Crucial RAM shows a CAS of 9 whereas the RAM currently in my system appears to be running at CAS 7 ???

That Crucial RAM is, basically, the same spec as the Corsair modules I pointed out in my first post so I am still none the wiser.

Bascially, will I be affecting system performance if I go for CAS9 RAM whilst my current RAM is running at CAS7 ?

I do have a sneaky suspicion though : Is this something to do with the RAM speed? IE: Is my current RAM running at CAS 7 because it is not running at it's full 1333Mhz speed? Would the CAS9 RAM that has been pointed out run at CAS7 if the speed were lower?
 

tokencode

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CAS Latency is the number of cycles the memory will wait. It does affect performance to some degree. The higher the speed memory, the large the CAS Latency. I would not mix and match memory, I'd by a full kit. CAS of 7 on 1066 is about the same as CAS 9 on 1333.
 

sp2011

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That's what I suspected :) So, I guess I will either buy the Crucial kit or 2 of the 4Gb SODIMM's from my local supplier (as referenced in my first post) - Any thoughts on this ?