I recall seeing some reviews showing that ram higher then 1600MHz did help with min. frame rates but the expense for it wouldn't be worth while IMO. However, something about it took my interest. The physics score in 3D11
. Which IMO is significant. It's unfortunate there aren't other games tested that uses a lot of physics in it.
Here's another interesting tidbit. 4gigs of DDR3 2133 CL9
did slightly better in min frame rates against 16gigs of DDR3 2133 ram at CL10 in 2 of the games tested. In that case 16gigs of ram isn't beneficial if you have higher latency. Although it would have been better to have a line graph to rule out with certainty any margin of error.
But to bring conclusion to this. It appears that latency and frequency is really dependent on the game. If you look at the game benchmark results from Anandtech
there is no real consistency from one game to the next. However, the general rule is if anything higher then ddr3 1600 cost similarly to ddr3 1600 then get it as long as the CL is lower then similar frequency ram. For example:
8gigs of DDR3 1600 CL7 or 16gigs* of DDR3 1600 CL7/CL8......at 1.5v if applicable
8gigs of DDR3 1866 CL8 or 16gigs* of DDR3 1866 CL9................at 1.5V if applicable
8gigs of DDR3 2133 CL9 or 16gigs* of DDR3 2133 CL9/CL10..at 1.5V if applicable
IMO is where you want to be. But at a price that justifies what you are getting and it' isn't too far off from DDR3 1600, again IMO.
* I've found that 4 stick kits of 16gigs of ram offering lower timing then what is readily available for dual stick kits.