What is the difference btwn Kingston HyperX Blu DDR3 v/s Kingston HyperX DDR3 ?

Tradesman1

Legenda in Aeternum
Both are native 1600/11 - and to run 1600/9 with the higher 1.65 voltage - the blue is blue and the other has a red heatsink. I wouldn't use either 1600/9 is entry level and over 95% of 1600/9 sticks run on 1.5, these needing 1.65 are indicative of weak memory chips