There is little to none improvement over 2.1V for this memory.

By the way, there is a trick to increase maximum stable clock , especially for 8GB configuration, which may or may not work for given set(s) and motherboard combination. Worked for me.

First, determine the maximum stable clock for each module in single channel configuration. Use memtest86+ to test stability,
10+ passes of test 5 and 5+ passes of test 4.

Then place all modules according the rule : best inserted in the sockets closest to MCH, worst -farthest. Works best for 4 dimm setup, but may also somewhat improve overclocking for two dimms.
For two dimms, they should be placed in the farthest pair of sockets (black on ASUS boards.)