What CAS latency to choose for memory for iMac 27-inch late 2012?
Hello! What memory latency should I choose for new iMac upgrade?
I see 9,10 and 11 CAS latency DDR3 1600 models being offered.
The best would be 9.
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Look at what is in your iMac right now, apple menu, About This Mac, More Info, System Report, Hardware, Memory and you can get the details of what is in there.
Also, buying from Mac specialists like OWC, http://www.macsales.com or Crucial, http://www.crucial.com will assure you of getting just the right memory.
OWC offers CAS 11. That means use 11?
Yes since OWC guarantees their ram to work. The memory works at peak speed when latencies match, and becomes important for systems using memory paging. The speed difference between an iMac with all modules matched and two matched/two unmatched will not be measurable by most users. You can follow that information path I gave above to check the latency of the installed ram. It may be the same as that of he OWC ram.
Use CAS 9 rated modules which will be faster than 11. CAS 11 is guaranteed to work because is isn't rated as fast as CAS 9 that may not work in some cases. However, Mac memory timing does support CAS 9 timing. If you want faster memory speed then use CAS 9 DDR3 1600 MHz.
I'm having the same problem as the original poster. I would like to get an extra 8 GB for my new iMac. I tried the "About This Mac, More Info, System Report, Hardware, Memory" but there is no information on the CAS latency and a google search of the product code didn't help me either.
Is there another way to check CL as I would like them to match? Other posts mention the clock frequency being downgraded from 1600 to 1333 MHz if you mix different CL.
Thank you
J
to find the type the easy way is to go to some of the memory makers site there one can choose 100% the model one have of imac then it will show what modules are supported and there one can read the CAS RAS settings
Well, It turned out that the best solution is just to plug the new memory in and plug the original out. That is the most sure case your momyry modules have exactly the same timings.
(I don't have to remind that aside from CAS latency there are a few dozens of other different latencies, do i? And it's better them all to match.)
Still, there are a lot of quiestions unclear:
1) How to know the CAS latency (and other) for the installed modules? The only idea is to install windows via bootcamp and run CPUZ. On the tab "Memory info" there will be stated main timings: CAS, RAS to CAS, RAS precharge, tRAS and tRC.
2) What is the minimum CAS latency officially supported by iMac 2012 27? PCs based on IvyBridge Intel beocessor usually have the minimum officially supported latence of 9 on 1600Mhz memory clock.
What CAS latency to choose for memory for iMac 27-inch late 2012?