You're cooling hardware isn't the problem, a great pump with good size of radiators and fans. Your GPU temps are great so that proves that. I would suggest that you re-seat your CPU and make sure that you get an even but thin application of TIM - put a tiny bit more on so that a tiny amount squeezes out from all the sides. Not much else you can do I don't think. If your chip is hot and throttling you are just going to have to take a lower OC. Or you can turn off hyper threading since it is useless for games. You could even turn off a couple of the cores because 4 is enough for gaming but there's no point having a 3930k then. Volts for that clock looks good.
Also, make sure you don't get confused between temperatures. The two temperatures we are talking about here are:
1. Tcase- the measurement of the cpu's integrated heatsink temperature.
Tcase MAX is listed by intel at 66.8C
here. It is useless for overclockers because it is defined at the stock volts. It is reported by the mobo in bios as CPU temp.
This is the figure that people commonly mistake for being the max temperature for cores which is why many forums say "keep the temps below 70C" or whatever. This is wrong!
2. Tjunction- the measurement of the cpu core temperatures.
Tjunction MAX on the 3930k is, I believe, 86C. At this temperature the CPU will turn itself off. Approximately 5C before this temperature the CPU will begin to throttle.
This is exactly why your cpu is throttling at 85C but you should not be so concerned about running in the 70Cs.
Ultimately I prefer to overclock using the response of the CPU rather than particular figures that are thrown around (although they can be useful guides). I keep increasing the volts and temp until the CPU throttles itself under stress conditions. At this point I consider the previous clock to be my stable overclock.
I stress that this is how I define my own overclock.
There is only one rule with overclocking - the higher the clock/volts the quicker you kill your CPU. So your own rules need to be defined by how regularly you intend on using your overclock and how hard you will use the CPU when overclocked. For example - a guy who F@H on his PC as often as he can should have a lower overclock than someone who only uses an overclock profile to game on for an hour a day if both people intend on having their CPUs lasting the same amount of time. But in either case an overclock should
never be set which throttles the CPU under stress conditions.