Please keep in mind that the Intel® AMT feature is a motherboard based feature, however in order to take advantage of this feature you need to have a Intel® vPro ready processor.
For a list of available Intel® vPro ready processors please check this link:
http://www.intel.com/support/vpro/sb/CS-030703.htm
If a particular processor does not support vPro, this is a marketing reason, since that depends on the market demands.