The thing is at this point a lot of latency comes from the fact that each dimm is physically displaced from the cpu. When you are on a timescale of nanoseconds

The thing is at this point a lot of latency comes from the fact that each dimm is physically displaced from the cpu. When you are on a timescale of nanoseconds even electricity's speed can be slow when being compared to something like intel's l4 cache which is on-die. For any type of volatile memory that latency will exist until mobo designers move the ram closer to the cpu or adopt optical interfaces between parts. For some cool calculations that can put things in perspective take the speed of light as 299 792 458 m/s and take the time of a nanosecond as 10^-9 seconds to get ~0.3 m/ns for light. That means that for every third of a meter the dimms are away from the cpu means a constant 1ns delay in terms of latency.