Has anyone worked with the JTAG debug tools from:
International Test Technologies µMaster 4010 for AMD® processor boards
http://www.intertesttech.com/ate/products_4010.htm
They also make a cpu interposers for boards that don't have JTAG or HDT connectors. The interposer plugs into the cpu socket and the cpu plugs into the interposer socket. They don't seem to have them for the latest AMD processors though.
http://www.intertesttech.com/ate/products_interposers.htm
-Bari