Your example is meaningless because it doesn't reflect physical reality.Zenmastur wrote:...I see I didn't answer one of the questions very well.
Namely this one:
Milos wrote: I also doubt you could gain much by running RAM on lower frequency. Usually total latency is pretty much constant for quite some range of frequencies.
I don't know why you think "total latency" is constant.
An extreme example might help clarify this question. Running DDR4 2400 at 10-12-12-28 1T vice running DDR4 2666 at 16-18-18-35 2T will show significant increases in NPS even though the 2400 is running at a lower speed. The difference is purely a function of latency. In less extreme examples, using the exact same dimms, small advantages can be had IN SOME CASES by running high speed dimms at lower frequencies and much lower latencies. This is mostly for those that are on a budget and want to get the highest possible NPS from their equipment. I've done this on a couple of my systems. This can require quite a bit of time tweaking the ram setting to get them just right. This is why not many people do it.
You can't run DDR4 at 2666 with 16-18-18-35 2T and in the same time at 2400 with 10-12-12-28. You can't magically cut down latency for 33% while reducing clock speed for 10%. It doesn't work that way.
Total latency or total delay is a product of clock period and number of latency cycles and this total delay is physical property of process node that you use to fabricate the memory. Memory controller on the DIMM is usually very well tuned to actual dies used on the DIMM that no matter what frequency (<= than maximum frequency) you run it at you get more less the same total delay.
Here is a little explanation:
http://www.crucial.com/usa/en/memory-pe ... ed-latency