Only the Ultras can make use of this. If you have a GT, or a non-ultra, you're not going to benefit from it and you'll experience a decrease in performance. This is because the GT's don't have the same amount of capacitors as the Ultras and they only use one molex connector. Getting the GT to run anything over 1.4V will only decrease performance, believe me, I've tried, and so have many others.
Having said that, it is much easier and cleaner to mod and flash your card's BIOS to squeeze out that 1.4V. Follow CandymanCan's guide in the nvidia section.