Intel do servers at all levels including low core count/high core frequency, where as AMD have a very decent core count, but, performance between the models is largely just an increase in core count (there is very little difference in frequency - e.g. NO high frequency/low core)
So many jobs still require Windows licenses unfortunately and since the shift to core count, it's ludicrously expensive to license a lot of the new AMD machines on SPLA licensing.
Not that I'm not trying though...