In most programs you won't see much (if any) real life difference between the fastest and the slowest ram, if you want faster ram then simply increase its speed and up its latency, you especially won't see any difference in gaming using a dedicated GPU. I have over the years realized a lot of ram is the same stuff or very close, clocked and timed differently, so different prices can be charge. I have collected a lot of memory modules over the years and for example I have 3 different modules of corsair vengeance ddr3, 1600mhz CL9, 2133mhz CL10 and 2400mhz CL11, each one of these modules can run at 2400mhz CL11 stable at stock voltage, my i7 3770k build still runs corsair vengeance ddr3 1600mhz CL9 @ 2400mhz CL11 and its 6 years old now and still stable. My new i7 8700k build has 32gb of crucial 2133mhz CL15, I bought it because it was the cheapest memory I could buy and I run it stable at 3000mhz CL17, which was just a guess setting I made when I first assembled the PC, it may run even faster at CL17 or its possible I could even lower the latencies, but I can't be bothered wasting the time for such miniscule improvements.
Here are the two faster modules up from my ram, which of course are more expensive:
http://www.crucial.com/usa/en/ct16g4dfd824a 2400mhz @ CL17
http://www.crucial.com/usa/en/ct16g4dfd8266 2666mhz @ CL19
My ram isn't just capable of these speeds and latencies, it surpasses them. Now sure this is not as fast as a lot of the memory out there, but it shows the relationship between latencies and speeds, take these ram modules for example:
https://www.amazon.co.uk/Corsair-CM...ir,p_n_feature_keywords_browse-bin:2841372031
https://www.amazon.co.uk/Corsair-CM...ir,p_n_feature_keywords_browse-bin:2841372031
These are most likely identical modules, one programed to run at 2400mhz CL14 and the other at 3200 CL16, but of course you will pay more for the 3200mhz CL16 modules or you could just buy the cheaper 2400mhz CL14 modules and run them at 3200mhz CL16. This is just one example, but I've been able to do this with almost every module I've come into contact with in the last 15+ years.