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General discussion

What does "CL" refer to on DIMMs?

Jan 23, 2004 6:22AM PST

Does anybody know what the "CL" spec. on the back of a DIMM module refers to? I've been shopping around for extra RAM for my laptop? It's currently using a 256MB 2100 266(FSB speed?) DDR DIMM with "CL12" but I've seen similar DIMMs that have "CL2.5". Is this "CL" spec. relivant when choosing RAM on a laptop? Thanks

Discussion is locked

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Re:What does
Jan 23, 2004 6:28AM PST

CL is commonly the Column Address Strobe Length in clocks. That would be too much to print on the chips, so the acronym could be CL. Since a CAS lenth of 12 is rather longish, I'd have to guess it was 15 which at such printing could be read as as 12, but it's not 15 (or 12) since some will drop the "." to fit the printing in.

And you should get memory from a place that will exchange it or stand behind your selection (like www.crucial.com)

Bob

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Re:Re:What does
Jan 23, 2004 7:05AM PST

I don't get ya Bob. Can you please be a bit more specific?

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Specific about what?
Jan 23, 2004 7:30AM PST

Remember that you can read about memory technologies at Crucial.com but I can't fit a course in computer design into this small space. If you want, use http://www.google.com and type in WHAT IS CAS? to find a definition.

What did you need to know?

Bob

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Re:Specific about what?
Jan 23, 2004 7:51AM PST

What I was getting at is: how relivant is the CAS specification in a DIMM to a PC/Laptop if you're looking to upgrade your RAM?

Thanks

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Very important.
Jan 23, 2004 8:05AM PST

"What I was getting at is: how relivant is the CAS specification in a DIMM to a PC/Laptop if you're looking to upgrade your RAM?"

Crucial and such vendors have selection guides to help you get the right speeds. CAS timing is just one of over 50 numbers you can measure in memory chips. Grabbing generic memory often works, but can really frustrate you if it doesn't.

Why not let Crucial or the other vendors get you the right memory?

Bob

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Re:Very important.
Jan 23, 2004 8:10AM PST

I see

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[NT] Minor point the "L" is for Latency,
Jan 24, 2004 7:59AM PST

.

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Now the picture is getting a little clearer.
Jan 23, 2004 8:15AM PST

You are definitely trying to find generic RAM to fit a laptop. In no uncertain terms I am warning you that many find this to be a frustrating experience as not only the SPEEDS of access time, CAS latency and more timing may have to be considered, but also the internal memory bank orginization of bank sizes and more.

Little revealed to you is that a 256 MB device can have a page size for the refresh circuitry to command or to interface with the laptop's memory controller. The owners of BX chipset based computers found out that many 256 MB sticks of memory were incompatible even though the timings were correct or better than needed. I have supplied a technical document as to why this was so, but in the end, the user is still unhappy because even armed with all the technical data, the stick of memory can't be used in their machine.

Let Crucial or someone else shoulder the work of determining if a certain stick of memory should work in your laptop.

Save yourself a lot of agony and time.

Bob

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Re:Now the picture is getting a little clearer.
Jan 24, 2004 3:00AM PST

I might just do that Bob. That was a really good site you recommended. Thanks