CAS latency and memory speed relationship?

  • Thread starter Thread starter davetest
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davetest

Hello,
in my bios, I can set either CL2 or CL3,
amd independantly of that, I can set memory speed,
for example, 5-2-2, 6,3-2, 6-2-3, or 6-3-3.

Are these settings related? If so, how should they best
be set?
thanks,
Dave
 
Hello,
in my bios, I can set either CL2 or CL3,
amd independantly of that, I can set memory speed,
for example, 5-2-2, 6,3-2, 6-2-3, or 6-3-3.

Are these settings related? If so, how should they best
be set?
Click to expand...

The CL2/CL3 setting specifies CAS Latency to Data. And in each of your four
sets of three numbers, the CAS Latency for both addresses of a two-dataphase
"burst" is specified in the last two numbers (the first number would be the
RAS Latency).

Obviously one setting must somehow override the other. Clearly, the CL2/CL3
setting is superfluous if you simply take the "memory speed" settings alone -
and it'd be my SWAG that the "memory speed" wins the day. Hopefully that info
is in the motherboard user's manual, otherwise you'll have to conduct some
"empirical science" to find out the answer ;-)

As for the last question: add the three numbers together for each set and use
the set with the lowest total that doesn't over-spec your DIMMs (ie: I
wouldn't bother trying a 5-2-2 setting if the DIMMs are spec'd to run 6-3-3 -
or "CL3").

If it works, you've tuned the memory to its fastest possible setting. If it
doesn't, use the next smallest "memory speed" setting...

/daytripper
 
Hello,
in my bios, I can set either CL2 or CL3,
amd independantly of that, I can set memory speed,
for example, 5-2-2, 6,3-2, 6-2-3, or 6-3-3.

Are these settings related? If so, how should they best
be set?
thanks,
Dave
Click to expand...

All depends on the specs of the ram you have,
and of course if they are compatible with the mobo.

Memory Guide, basics, what the numbers means, etc....
http://www.corsairmicro.com/memory_basics/153707/index.html

Stand-Alone Memory Diagnostic testers
http://www.memtest.org/
http://www.memtest86.com/
http://oca.microsoft.com/en/windiag.asp

Ed
 
Gentemen, thanks for the info.
My board listed 633 as normal, 632 as enhanced, 623 as fast and
622 fastest. Based on this it seems as if the first two would
correspond with cl3, while the faster two must match up with
cl2.
I'm going to check out the corsair site for background.
Cheers,
Dave

PS my board is an older kt133a and memory is crucial CL2.
However, I have had some unusual events using 622, such as mpeg
encoders and other apps simply disappearing in XP PRO.
One minute it was encoding, then it was gone.
No error message, nothing.
Secondly, I set the bios to performance defaults which
uses 633 and cl3. Using sandra and aida32 and their
benchmarks, the difference between this setting and
622 cl2 was tiny, less than 1%. I would have thought it
should have been more, but I couldn't measure it.
 
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