First off, most 2600k's will not reach above 4.6ghz without a very high voltage. That is much too high even for the H100 to handle. Settle for a 4.5ghz OC and read this guide: http://www.tomshardware.com/forum/266189-29-sandy-bridge-series-ocing-cores-guide
I was able to get my 2600k @4.6ghz stable with a 1.375V, but this does not mean your chip will need this voltage or hit this speed at this voltage. Some people have even been lucky and were able to hit 4.6 with a 1.295v! Don't blame any of your settings, blame the chip.