@jkauff, what do you mean with " If you have to go higher than 1.35, I wouldn't bother. The performance gain won't be worth all the extra juice you'll be paying for " ???
So, it wouldn't be worth to go higher than 4,6 GHz ??
Increasing voltage leads to exponential increase in power consumption, hence it's worth to increase voltage only by small margins in order to increase frequency. Once you go high enough in frequency (4.5-4.7Ghz) you will encounter a point at which the chip will require a big jump in voltage in order to stay stable. That big jump in voltage may not be worth it, since it would lead to high power usage and likely high temps as well.
Also, whatever games you're playing, a jump of 100Mhz is not going to influence your framerate. You already made the "big" 10% jump from 4.2 to 4.6Ghz.
Here's an example of an overclockign table from the Anandtech review of 4790K. Notice how going from 4.6Ghz to 4.7 required a big jump in voltage, accompanied by high power consumption and very high temps.
Now, your chip might be better than that, but if you cannot get it stable at 1.35V as advised, it's probably a good idea to settle with 4.6Ghz and call it a day after making sure it's stable.