What is a CL9/CL7 Ram?

[anroin]

For example,what is the difference between a 1333 Mhz CL7 ram and 1333Mhz CL9 ram?

Also,I'd like to ask that if a motherboard supports the bus speeds 1333/1600/2000(O.c.) does this mean it can use 1333 and 1600 Mhz memories but you'll have to overclock to make it use 2000? Or would you have to change some settings to make it use 1600 as well?

Thanks

 

[gkay09]

CL is timings/ latency, and generally lower is better
Detailed description -
http://en.wikipedia.org/wiki/CAS_latency

As for your next question,
The default speeds that will be set when using the RAM on the board would depend on the CPU that you would use...Generally they are either 1066/ 1333MHz at the max I have seen(both from Intel and AMD), so for anything above, you would have to set them either manually in the BIOS or if using certain Intel CPUs, you can make use of the XMP profiles(the RAM should have XMP profiles)

 

[intel1502]

I tend to just think theoretically of it as
CL7: Race starts - waits 7 seconds - GO! @ 'x' speed
CL9: Race starts - waits 9 seconds - GO! @ 'x' speed

 

[anroin]

CL is timings/ latency, and generally lower is better
Detailed description -
http://en.wikipedia.org/wiki/CAS_latency

As for your next question,
The default speeds that will be set when using the RAM on the board would depend on the CPU that you would use...Generally they are either 1066/ 1333MHz at the max I have seen(both from Intel and AMD), so for anything above, you would have to set them either manually in the BIOS or if using certain Intel CPUs, you can make use of the XMP profiles(the RAM should have XMP profiles)

So,would a 1600 Mhz Ram run at 1333 Mhz until the setting are changed or would it malfunction?

 

[andrern2000]

The 1600 RAM will run at 1066/1333 Mhz, but will function, unless it's broken then malfunct. Also preferably included in compatibility list of mobo's supported memory.
You see, BIOS has default settings for most RAMs newly recognized as 1066 or 1333. You have to set it manually through BIOS to set it to advertised speed: speed, timings, and voltage.