RAM question about CAS-2

[will729]

whats the difference between 512 PC133 and PC133 CAS-2?

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I AM WILL729 I DON'T NEED A SIG!!!

[will729]

the 512 meant 512MB of PC133 and 512MB of PC133 CAS-2. i just want to know which is better and, if you feel like it, why

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I AM WILL729 I DON'T NEED A SIG!!!

[This message has been edited by will729 (edited 11-05-2000).]

[ixl]

"CAS" stands for "column address strobe". It's a timing specification. CAS2 memory is 1 or 2 % faster than CAS3, which is an issue for some people who are overclocking, and unimportant to anyone else IMO.

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Charles M. Kozierok
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[kenja]

I recall reading (crucial.com) that CAS3 DIMMs are made on the same assembly line as CAS2. They just don't quite meet the more rigorous specification.

If CAS2 is just a few bucks more, I buy that. You'll notice that as a manufacturing process matures (like for PC100), the CAS3 chips are no longer being sold.

CPU manufacturers do much the same thing when they "bin" their chips by speed (frequency) rating, within a given line.

[kenja]

I've been looking some into overclocking, and the newer CPUs have the "clock multiplier" locked, so I guess the CPU manufacturers no longer do "binning".

[kenja]

Here's a relevant link: http://support.crucial.com/scripts/crucial.exe/solution?11=000724-0010&130=000964475444&14=&2715=&15=&2716=&57=faq&58=&2900=NLBb5iqOu2&25=-1

[hiredgoonz]

CAS is the memory latency...the way I understand it is this: the number corresponds to how many cpu clock cycles it take to access ram...so 2 or 3 clock cycles...

What does that mean in the real world? if you have a 500 mhz chip it runs at 500 million clock cycles per second, so one clock cycle every 2 nanoseconds, so if it takes 2 clock cycles to access memory it takes 4 nanoseconds, for CAS 3 it takes 6 nanoseconds, so if you think you'll notice a 2 nanosecond difference http://www.PCGuide.com/ubb/smile.gif

The difference gets even smaller as the chip speed increases, but if the difference in price is only a few dollars you'll probably regret it if you buy latency 3..my mobo gives me an annoying "helpful hint" to set the latency to 2 if I set it at 3...