DDR3-1333 SDRAM: Do you own modules with CL7 programmed as JEDEC values



Just out of interest: Do you own 1333-modules that have 7-7-7-x programmed as JEDEC values and not as additional XMP values into the SPD? I ask because the wikipedia article claims that JEDEC specified 1333 CL8 and 1333 CL7 modules. I don’t think JEDEC specified 1333 CL8/CL7 chips as well. But that one is just my personal guess. But if JEDEC at least specified 1333 CL8/CL7 modules, did they specify those to 1.5V operation?

I know that practically it’s the same when XMP sets the CL7 timings, but I just would like to know for having the background knowledge. If you indeed own JEDEC CL7 1333-modules, do you have any clue whether your chips are native CL8/CL7 ones and therefore the real thing I’m asking for with this posting? Theoretically it still could be CL9 chips with just the SPD programmed to CL8/CL7. Native 1333 CL7 chips would run cooler and would need less power as well I guess (yes, I know there’s the 1.35V lovo spec…). But since even Micron does not make such (I looked at their parts catalog) I guess there is no native CL8/CL7 1333-chip at all.


I remember a few years back someone made a program to set your own JEDEC values and flash them into the RAM stick, pretty cool.

There should be at least CL8 at 1.5 in JEDEC, but CL7 is pushing it. Most MB’s bios use the relaxed CL9 to boot with a higher success for the first time. Not everyone realizes that so they don’t run their RAM at full potential. Most average MB’s don’t even have the XMP feature to draw on the faster values and users are too afraid to mess with memory timings.

Most RAM chips begin their life as CL9 but are “binned” to find the faster ones where they get sorted to whether they make it to CL8 or CL7. Others are just simply a higher-end manufacturing process that gets better yields of the CL7 or even CL6.