I've _never_ needed to plug-in the EZ_PLUG_2 connector for Corsair Vengeance 1.5V RAM on multiple builds with this board.
It won't hurt to plug it in, but I doubt it will have any impact at all in regards to this issue. (It's meant for higher speeds/voltages.)
Also, the only 'issue' with Corsair Vengeance RAM + this board I have encountered is that sometimes automatically setting RAM parameters via XMP may not work if you aren't using matched kits.
MB: ASUS Rampage IV Black Edition
CPU: Intel Xeon E5-2697 v2 (Cooled by Corsair H100i w/ Noctua NF-F12 fans)
RAM: 64GB G.SKILL RipjawsZ 1600 (10-10-10-30)
GPU: EVGA GeForce GTX Titan X Hybrid
TV Tuners: 2 * Hauppauge HVR-1800
Case: CoolerMaster Cosmos 2