The speeds and voltages are in an acceptable range for a 4770K. OCCT is a more stringent test than linkpak, Aida, Prime95, Realbench or XTU. I get the same results: OCCT needs more volts to show stability. I think of OCCT stability as 'unconditional stability' because 'stability' at any of the lesser levels gives me blue screens in everyday work. My 24/7 profile will always be OCCT stable. When I'm pushing a benchmark, that profile may be no more stable than the particular benchmark needs.
Adaptive voltage with Turbo enabled will stick an additional 0.1 volts onto Vcore when the CPU sees certain instructions in the program -- most notably AVX instructions. A jump from a 1.3v setting to 1.4 is as expected. Adaptive voltage with energy saving will keep the average temperature cooler -- a good thing. If the profile is stable with a manual 1.3, it will work. Lower peak voltage is less alarming, but the CPU will draw moderate power all the time. Stability is the operative criterion. I would consider 1.3 to 1.4 volts 'safe' along with the water cooling of the Swiftech kit, but the power levels would be beyond air cooling.
The CPU works well with cache clock within 300MHz below the core clock. Within 200MHz is better , eg. 4.1ghz or more with a 4.3ghz core. There is no benefit to cache clock higher than core. The rule of thumb I use is to set cache clock 200MHz less than core and set cache voltage equal to Vcore -- manual or adaptive the same as core. Check for stability in OCCT, then step Vcache down .01 volts per step until OCCT finds an error, does a freeze-up or BSOD. Then I set Vcache to the lowest stable voltage step. If the stable Vcache is higher than Vcore, drop cache clock to 300MHz below core and repeat the voltage stepping. I know that sounds tedious, but that's the nature of OC tweaking.
All the above are opinions based on my experience with several Haswells. Hope they help.
Jeff