Test in your apps and see if you find a difference. Benchmarks may show better but 16GB RAM with the 2x8GB would be my choice since it's a pair, and more than ample for most users. From 16 to 24 should be almost unnoticeable.
I have 24gb ddr3 running on a gigabyte 970A-DS3P
"2 x 8gb kinston hyper fury x 800mhz and 2 x micron 4gb 667 mhz am i better off with the two kinston ram modules 16gb or with the micron ram as wel 24gbl. thanks in advance grangler