It's been suggested that 1.45V is the maximum safe 24-7 with a 6700K, so I'd imagine the same is with Kaby Lake. To be conservative, probably no more than 1.4 V. I suspect that delid would lead to further improvements in performance, perhaps 100-200 MHz and much cooler temperatures. There have been claims of more than 20-C delidded, which considering the history of delidding isn't improbable. Combined with delidding, most people could probably get 5 GHz at 1.4V, perhaps a few even going as 5.1 or 5.2 GHz. Thanks for the preview. Looking forward to the full review. CPU progress seems to have stalled. We are basically at 2600K speeds, only with Skylake IPC, more or less and faster DDR4 RAM. I guess the only other real improvement is DMI 3.0, which is valuable for an NVMe SSD. Hopefully this means that the Skylake X will OC as well as a 6700K. A 5960X could do 4.4 to 4.6 GHz at 24-7 voltages, which was pretty much the same as a 4770k. 4790K could do perhaps 250-300 MHz better on average.