All I know is 1.65v technically overclocks the IMC and voids your CPU warranty. That is from Intel themselves. Kingston is also the only company still selling DDR3 1600 that takes 1.65v. I don't know if they just have a huge stock of old DIMMs or they are just using low quality modules. Either way I would trust Crucial over Kingston.
You will get lower overclock temps if you are not overclocking the IMC as well.