* Core i3-8100 [0]
* Core i5-8500 [1]
* Core i7-8700 [2]
All of these are listed as having embedded version available, which I would expect Apple to be using, since embedded versions of desktop SKUs in the iMac.
[0] http://ark.intel.com/products/126688
[1] http://ark.intel.com/products/129939
[2] http://ark.intel.com/products/126686