O.P., I also have a H100i but with a daily ran 3770k O.C. to 4.2ghz. My Temps are usually in the mid/high 40's under normal gaming use and using Prime95 under full load into the mid 50's).
Your temps are ok if its stressing the CPU heavy as the 4770k does run a SLIGHT bit hotter than the 3770k, You will not do damage until you are over 70deg. as according to Intel your Thermal Limit at the IHS is 72deg. Celsius ( http://ark.intel.com/products/75123/
) However you can adjust your fan profile to ramp up a bit earlier if you feel the need to run cooler. With that said the thermal paste that comes on the Corsair water block while not bad is certainly not the best and I did notice a 2-4deg drop in avg. temps using PK-1 also how is the airflow on the case? What case do you use? This matters because if the air in your case is getting really warm from your GPU than it will not cool as effectively. Is your H100i pulling air from inside the case or fresh air from outside the case? Just a couple of variables that can change the result.
Best way to know if your O.K. for sure is run Prime 95 on all cores for about 30min. If the temps get over low 60's than you should stop Prime95, and either try to increase cool air going through the radiator or to try re-seating your CPU block This would require cleaning both the water block and the IHS (Integrated Heat Spreader or "Lid") and applying new thermal paste. I prefer the grain of rice method running down the center of the IHS inline with the actual processor about 1/3 to 1/2 the length of the IHS If you dont know how the processor is orientated.. I will reference the gold triangle on the PCB if on the top right and the cluster of gold dots on the PCB are on bottom it is a vertical line down the middle. If you need tips on cleaning the block and IHS and applying new TIM please let me know or there are about 1000 videos on the subject online. CLEANING AND PROPER APPLICATION of the TIM is crucial for good temps as air bubbles, to little or to much TIM are all a bad thing. Also when seating the bock it just needs to be snugly hand tightened in a cross pattern. Over tightening of the block can damage your motherboard.
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