If you want to most extreme memory money can buy, Corsair now has a Vengeance LPX DDR4 memory kit that is guaranteed to hit 5000MHz.
This dual-channel memory kit offers two 8GB modules that run at 18-26-26-46 timings at 1.5V.
VENGEANCE LPX memory is designed for high-performance overclocking. The heatspreader is made of pure aluminum for faster heat dissipation, and the eight-layer PCB helps manage heat and provides superior overclocking headroom.
The pricing of a 5000MHz 16GB DDR4 kit? Corsair charges $1,224.99 via its webshop.