Is it true that the i7-6700k only turbo boost single core loads? According to the official Intel i7 6th Gen turbo boost table that's what is shown but a couple of reviews I read said that by default it 4.2 GHz turbo boost on all core loads but I think I'm going to more likely believe what a table from Intel says it is than a review from the internet as some motherboards have options to boost all core loads to full turbo boost speed:
http://www3.intel.com/support/processors/corei7/sb/cs-032279.htm
http://www3.intel.com/support/processors/corei7/sb/cs-032279.htm