RAM information

Sorry if this is a dumb question but I have always been on the software side of things as opposed to the hardware (at least for low level details) but could someone please explain what C13,C14,C15,C16 Etc..... What is that "C" number? Also for timings, are higher timing slower and lower timing numbers faster?

If someone could help explain this I would really appreciate it, I have been googling the hell out of it and can't find anything...

C? Do you mean CL? That should be CAS latency and is along with command rate the most important timing of a RAM module.

Has to do with number of clock cycles it takes to read and write to RAM, the lower the better

Simple math (though not all encompassing) take the CL, lets say 11, and the mhz, lets say 1866.

11/1866 -> .005894

to compare with say, cl 8 1600mhz ram

8/1600 -> .005 even

So CL 8 1600mhz ram should be "faster" than cl 11 1866mhz ram. Though, not all applications work in this manner, its a pretty good dummy test to see which ram you should get. CL 15 1866mhz would be quite inferior to a higher quality 1600mhz for instance.

What about CL 15 2666mhz ddr4 ram?
Does this formula work the same for DDR4 ram?

Asking because I have the 64gb of corsair dominator platinum (2666mhz)
http://www.corsair.com/en/dominator...ram-2666mhz-c15-memory-kit-cmd64gx4m8a2666c15

Snowbiz said:

What about CL 15 2666mhz ddr4 ram?
Does this formula work the same for DDR4 ram?

Asking because I have the 64gb of corsair dominator platinum (2666mhz)
http://www.corsair.com/en/dominator...ram-2666mhz-c15-memory-kit-cmd64gx4m8a2666c15

Click to expand...

Well DD4 has higher latency then DDR3, its cycle since early rams. Like old SDRAM had like CL 2 or 3 for example. The higher the speed the more latency.

Memory itself can be faster or slower but memory controller makes it fast or slow in real-life work. Memory on AMD can be 30-50% slower than on Intel even though you can use exactly the same RAM. Even Intel can be faster or slower than Intel. All depends from memory controller, cache speed etc. Like Ivy Bridge has higher read bandwidth than Haswell but lower write bandwidth.
These quick calculations are only theory. Sub timings are affecting memory performance too much to say that only CL or main timings and clock make memory fast or slow.
DDR4 is not exactly next stage of DRAM which is higher clocked but has slower access time. There are too many factors to describe it right now. Lets just say DDR4 speed on current chipset ( the only available X99 ) depends more from cache speed and memory clock than timings but without high cache speed, memory speed will be never high regardless how high you set memory clock.

2666 15-17-17 1.2V is just standard DDR4 memory but not many manufacturers are using tighter timings for 64GB kits. Some manufacturers are selling 2666 14-14-14 1.35V or 2666 15-15-15 1.2V which will be faster but you won't see difference anyway.

Here you have my Corsair Vengeance LPX 2666 CL15-17-17 test and comparison in couple of benchmarks at various settings ( right click and view picture to see it better ):
http://www.overclockers.com/forums/...e-LPX-4x4GB-DDR4-2666-CL15-CMK16GX4M4A2666C15