SQL Server switched from CPU-based licensing to core-based licensing as of their 2012 version and they included a "core factor" that reduced licensing costs if you were running on AMD cores to 75% of the cost for Intel cores to account for AMD's then-lower per-core performance.
That applied only to certain AMD CPUs that were available in 2012. It's just an example in which there was some effort to take a "fairer" approach to per-core licensing. It's especially notable since the EPYC line is evidence of the great strides that AMD has made since then when MS just gave you a blanket discount for running SQL Server on AMD cores.
http://download.microsoft.com/download/7/3/c/73cad4e0-d0b5-4...