Apple's A10 silicon (from the iPhone 7) already beats Intel's 12-core Xeon from the Mac Pro in single-thread.
http://www.theverge.com/2016/9/16/12939310/iphone-7-a10-fusi...
http://www.theverge.com/2016/9/16/12939310/iphone-7-a10-fusi...
I can list about 150 programming languages that are "faster than C" if you apply similar restrictions.
Also it's 4 year old Xeon. If you're going to compare it to a 4 year old Xeon, compare it to the 2 core versions, which will have much higher clocks.