So from what I can see you have your memory at 3800MHz and your IF at 1900MHz.
Your using the timings that are from your DOCP profile which are usually for 4000MHz and your getting a latency of 66ns?
I think that's pretty good and would be very happy personally to leave it there to be honest.
You CAN get faster as those timings are quite loose, but anything under 70ns latency is very fast anyway so unless you like fiddling and playing around, you CAN stop there and say job done.
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What mobo do you have by the way?