Could you please attach the result of the Intel® Processor Diagnostic Tool?
Also in case your processor was under the Tuning Protection Plan, https://click.intel.com/tuningplan/, if it is necessary you can contact our support center to process the replacement:
Btw, I recommend you to take a look on this website for further support on Overclocking
Also, here you can find Two Intel® Tools Simplify the Overclocking Process,
First of all on Asus mainboard you should set CPU voltage to Adaptive, on auto will stay all time on maximum voltage.
On Adaptive when is in idle will have about 0.7V and when under load 1,2V.
If you have high temps on stock frequency, you should check if that water cooler is working and mounted correctly.