Question about RAM CL

Question

Hi guys. I'm finalizing my PC build and have a question about ram CL that I cannot find answers to on the tweakers page here. http://ppbm7.com/index.php/news/planning?showall=&start=3
I'd like to use these two ram sticks as an example.
Transcend JetRam™ High-Performance 8GB DDR3-1333 240-Pin Module : CL9, 6-Layer PC Board
Transcend JetRam™ High-Performance 8GB DDR3-1600 240-Pin Module : CL11, 6-Layer PC Board, Ultimate cross-platform compatibility and stability
My question is, which is better for video editing? On the one hand we have 1333mhz at with a CL of 9. On the other, we have faster 1600mhz ram, but at a higher CL of 11. Now, I'm not one to get caught up in the technicalities like it may seem, but I do want to understand these so I can make informed decisions, especially when price is a factor. In this case however, they are the same price...

Answer 1

From http://ppbm7.com/index.php/news/cpu-mobo
Make up your mind about the number of memory sticks you want to install. On the X79 platform, do you want to use 4 slots, or do you want to fully populate all 8 slots? This is very important especially with i7-3930K / 4930K CPU's, which have a rather finicky memory controller.
Make a shortlist of quad or octo packs of memory sticks in the size you want, limiting yourself to ONLY sticks using 1.5V or less.
Check the motherboard manufacturer's site QVL list to see which of the sticks on your shortlist are approved. Pay attention to the number of slots for which they are approved. Some modules are approved for 4 slots only, others for fully populated use.
Check the memory manufacturer's site QVL list to see which motherboards are approved.
Try to establish if there are users that have been successful in using the sticks on your shortlist and delete any that were giving trouble to others. NewEgg can be a good source for that.
Now that you have a very short shortlist, contact the Technical Support departments of both the motherboard manufacturer and the memory manufacturer and ask them to confirm or deny the compatibility of the memory modules in the quantity you need.
If both confirm compatibility, check the physical height of the modules including heatsink in relation to the intended CPU cooler. Do they fit without modding?
In general, only buy matched sets of memory sticks. There are too many different sticks with the same type number, that will cause grief when bought as four single sticks, but you limit the risk by only buying quad sets or octo sets for fully populated X79 platforms.
CAS latency is no longer important, in fact, with the finicky nature of the memory controller of the Sandy Bridge-E, it can be advantageous to choose a higher CAS latency for improved compatibility. What can be important - relatively speaking, only in single digit % performance differences - is the rated speed of the memory, 1333 or 1600 or 2133 or even 2400.
Even though the X79 platform only supports - at least officially - up to DDR3-1600, one can use XMP profiles in the BIOS to have the memory run at its rated speed of say 2133. For my new 'Monster' I followed these steps and ended up with a fully populated 8 x 8GB octo set of G.Skill RipjawsZ F3 DDR3-2133 sticks that are running without any problems at 2180 MHz.