As others have said, clock speed isn't necessarily a measure of performance or even raw performance. Unless it's purely to have the highest clock speeds to put down on paper then yes, amd does have the highest clock speeds. But because ipc (instructions per clock or performance per core) isn't comparable, they're not the 'fastest'.
That would be the i7 6700k or 4790k. Technically the 4790k has higher clock speed by a couple hundred mhz but due to ipc improvements on the 6700k they're pretty close to one another despite the slightly lower clock speeds on the 6700k. Both are clocked faster than the 6/8 core 2011v3 cpu's including the 5960x flagship extreme cpu. In order to keep overall tdp down as the number of cores increases their...