Just a week after the official launch of the Intel Devil's Canyon processors, Toppc submitted a 6842 MHz CPU-Z validation with the Core i7 4790K. For this he uses an MSI Z97 XPower AC motherboard and close to 2V on the CPU. Looking at the CPU-Z Frequency ranking at HWBOT, we see that the 6.8GHz is still quite a bit off the best Haswell validation (which is well over 7 GHz).
I suppose we will see more of Devil's Canyon in the future. Keep you guys updated!